CriticalCVE-2016-4117

Adobe Flash Player Arbitrary Code Execution Vulnerability (CVE-2016-4117)

Published 11.05.2016Last modified 10.09.2026In CISA KEV since 03.03.2022Sources: CVE.org

What is affected, what to do

A remote code execution (RCE) vulnerability exists in Adobe Flash Player 21.0.0.226 and earlier, allowing attackers to execute arbitrary code without authentication. This vulnerability is actively exploited in ransomware campaigns and poses a critical threat. Affected products include Red Hat Enterprise Linux Desktop, Server, and Workstation. Immediate patching to the latest version of Adobe Flash Player is crucial to mitigate this risk.

The vulnerability is being actively exploited; treat it as a priority. CISA lists it as used in ransomware campaigns. The available sources name no fixed version. Check the vendor guidance in the references below. Immediate actions, mitigation and detection rules are in the runbook below.

Affected: Adobe Flash Player lte *..21.0.0.226
Redhat Enterprise Linux Desktop eq 5.0..5.0
Redhat Enterprise Linux Desktop eq 6.0..6.0
Redhat Enterprise Linux Server eq 5.0..5.0
Redhat Enterprise Linux Server eq 6.0..6.0
Red Hat Enterprise Linux Server From Rhui eq 5.0..5.0
Red Hat Enterprise Linux Server From Rhui eq 6.0..6.0
Redhat Enterprise Linux Workstation eq 5.0..5.0
Redhat Enterprise Linux Workstation eq 6.0..6.0
openSUSE Evergreen eq 11.4..11.4
OpenSUSE eq 13.1..13.1
OpenSUSE eq 13.2..13.2
SUSE Linux Enterprise Desktop eq 12..12
SUSE Linux Enterprise Workstation Extension eq 12..12

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Metrics

9.8

Priority

XIEM Effective CVSS: highest available CVSS rating from NVD and vendor data.

Source: NVD, CVSS v3

9.8

CVSS v3

Severity Critical on the scale from 0 to 10.

Source: CVE.org

94.3 %

EPSS score

High — model estimates ≥ 50% chance of real-world exploitation within 30 days.

Source: FIRST EPSS, percentile 99.85

Show all metrics

Severity: Critical
Priority (0–325) The priority score is a consolidated metric that condenses several individual signals into a single, action-guiding ranking: technical severity (CVSS), exploitation likelihood (EPSS), known-exploited status (KEV) and the context of the affected asset. The aim is to answer the only truly important question in vulnerability management: what first? Read in glossary: 253.76 Methodology
Exploit maturity An exploit is code or a technique that specifically uses a concrete vulnerability to force unintended behaviour — such as executing code or escalating privileges. It is the tool that turns a theoretical flaw into a practical attack. Read in glossary: actively exploited
XIEM Effective CVSS XIEM® is the tiered managed-security operating model from NEOSEC and a registered trademark of NEOSEC GmbH. It extends classic SIEM — the central collection, normalisation and correlation of security-relevant events — with endpoint forensics, network visibility and deception technology, and consolidates them into three building tiers: Sentry, Orchestrate and Command. Read in glossary: 9.8 Methodology
CVSS v3 CVSS is the globally established, open standard for assessing the technical severity of a vulnerability on a scale from 0 to 10. It describes how easily a flaw can be exploited and what damage it can cause — but not how likely its actual exploitation is. CVSS and the complementary EPSS deliberately answer different questions. Read in glossary: 9.8
EPSS score The EPSS score is the absolute model output for an individual vulnerability: the estimated probability of real-world exploitation within the next 30 days, expressed as a value between 0 and 1 (i.e. 0 % to 100 %). A score of 0.42 means „the model estimates a 42 % chance of real-world exploitation within 30 days“. Read in glossary: 94.3 %; High — model estimates ≥ 50% chance of real-world exploitation within 30 days.
EPSS percentile The EPSS percentile is the relative position of a vulnerability within all EPSS-scored CVEs, expressed as a value between 0 and 1. A percentile of 0.90 means „this CVE has a higher EPSS score than 90 % of all other scored CVEs“. Unlike the EPSS score, it is not a probability — but a positioning within a ranking. Read in glossary: 99.85; Critical — this CVE ranks in the top fifth of all CVEs scored today (rank ≥ 80%).
KEV status The KEV catalogue is a list maintained by the US authority CISA of vulnerabilities for which active exploitation in the wild has been confirmed. It answers not the question „how severe?“ but „is it already being attacked?“ — thereby sharply prioritising patching. Read in glossary: Actively exploited
Published: 11.05.2016
In CISA KEV since The KEV catalogue is a list maintained by the US authority CISA of vulnerabilities for which active exploitation in the wild has been confirmed. It answers not the question „how severe?“ but „is it already being attacked?“ — thereby sharply prioritising patching. Read in glossary: 03.03.2022
CISA assessment (SSVC): Exploitation: active · not automatable · Technical impact: total; Source: CISA Vulnrichment, as of 3 February 2021

Response and mitigation

Why act now?

Prioritisation rationale

The flaw is network-reachable without authentication and needs nothing more than a visit to a crafted web page or the opening of a document. It was used heavily in drive-by and malvertising campaigns, and CISA explicitly flags known ransomware use. It sits among the CVEs with the very highest exploitation likelihood. Because Flash has been unsupported for years, any remaining installation — typically on legacy workstations, OT-adjacent operator consoles or forgotten RHEL desktops — should be treated as a critical finding. The remediation is "remove", not "patch", which also gives you a clean evidence point for NIS2 vulnerability-management reporting.

01
Runbook step 1
Immediate response (0-24 h)
- Inventory every Flash installation: Sweep endpoints and servers for Flash.ocx, NPSWF*.dll, pepflashplayer*.dll (Windows: C:\Windows\System32\Macromed\Flash\, C:\Windows\SysWOW64\Macromed\Flash\). Also check for the flash-plugin package on RHEL Desktop/Server and openSUSE/Evergreen, e.g. rpm -qa | grep -i flash. Adobe Flash Player 21.0.0.226 and earlier is affected.
- Uninstall Flash outright rather than patching: Flash Player is end-of-life and receives no further security updates. The original fix is available from the vendor — check the vendor advisory for the exact version — but continued operation is not defensible. On Windows, push the Adobe uninstaller or Microsoft's Flash removal update via WSUS/Intune. On RHEL/openSUSE, run yum remove flash-plugin or zypper rm flash-player.
- Isolate systems that genuinely depend on Flash (legacy HMIs, old web management consoles, training kiosks): remove their internet and email access and move them to a dedicated segment with no browsing.
- Triage hosts found with Flash ≤ 21.0.0.226 for compromise: Review EDR history for child processes spawned by browsers or Office (see Detection rules). Given CISA's ransomware flag, prioritise checks for encryption activity and persistence.
- Rotate credentials on confirmed hits: Reset passwords for users logged on to affected endpoints and for local admin accounts wherever execution traces are found.
02
Runbook step 2
Mitigation layers
- Configuration / endpoint hardening: Block Flash globally through GPO and browser policy (Chrome/Edge plugin policies, Firefox plugins.flashBlock.enabled). Set the ActiveX kill bit for the Shockwave Flash CLSID {D27CDB6E-AE6D-11CF-96B8-444553540000} via GPO. This also stops SWF embedded in Office documents.
- Application control: Use AppLocker or WDAC rules to deny loading Flash.ocx, NPSWF*.dll, FlashPlayerPlugin_*.exe and FlashUtil*.exe. On Linux, remove or lock down libflashplayer.so via fapolicyd or file permissions.
- Web proxy / secure web gateway: Block application/x-shockwave-flash responses and .swf/.spl downloads organisation-wide. Allow exceptions only with a documented risk acceptance.
- Email gateway: Quarantine Office documents (RTF, DOC, XLS, PPT) that contain embedded Flash objects (ShockwaveFlash.ShockwaveFlash, SWF headers FWS/CWS/ZWS).
- IPS: Run Suricata/Snort rule sets (e.g. ET Open/ET Pro, exploit-kit and Flash-exploit categories) in blocking mode. Malvertising and exploit-kit landing pages were the dominant delivery path.
- IAM / least privilege: Make sure users run without local admin rights, so that browser-context code execution does not immediately become system-wide control.
03
Runbook step 3
Detection rules
- Sysmon EID 1 / EDR process ancestry: Look for suspicious children of iexplore.exe, firefox.exe, FlashPlayerPlugin_*.exe, plugin-container.exe, winword.exe, excel.exe or powerpnt.exe — e.g. cmd.exe, powershell.exe, wscript.exe, rundll32.exe, regsvr32.exe. Sigma shape: ParentImage|endswith: [...] AND Image|endswith: ['\cmd.exe','\powershell.exe','\rundll32.exe'].
- Sysmon EID 7 (image load): Flash.ocx loaded into an Office process strongly suggests a weaponised document. KQL: DeviceImageLoadEvents | where FileName =~ "Flash.ocx" and InitiatingProcessFileName in~ ("winword.exe","excel.exe","powerpnt.exe").
- Sysmon EID 11 / file system: Executables (.exe, .dll) written to %TEMP% or %APPDATA% by browser or Flash processes and then executed. Mass renames or ransom notes afterwards indicate ransomware.
- Zeek files.log / http.log: A SWF download (mime_type == "application/x-shockwave-flash") followed within seconds by an executable download (application/x-dosexec) to the same client. This is the classic exploit-kit chain.
- Standing inventory rule: Run a recurring query (SCCM/Intune/osquery: SELECT * FROM programs WHERE name LIKE '%Flash%'). Treat any hit as a compliance finding.

Detection rules

No NEOSEC detection rule is available for this vulnerability yet.

Classification under NIS2 and CRA

Rule-based classification from exploitation status and severity. It does not replace a case-by-case assessment.

NIS2 NIS2 is EU Directive (EU) 2022/2555 to raise the level of cybersecurity across the Union. It substantially broadens obligations compared with the first NIS directive: more sectors, mandatory risk management, staged reporting duties and personal accountability of senior management. Read in glossary: Actively exploited: treat the vulnerability as a priority in vulnerability handling under Art. 21(2)(e) NIS2. If it is exploited in your environment, check the reporting obligation under Art. 23 (early warning within 24 hours).
CRA The CRA is EU Regulation (EU) 2024/2847 setting horizontal cybersecurity requirements for „products with digital elements“ — from industrial controllers and software to connected consumer devices. For the first time manufacturers must ensure security across the entire product lifecycle, handle vulnerabilities and provide security updates. Read in glossary: Since 11.09.2026, manufacturers of affected products with digital elements must report actively exploited vulnerabilities under Art. 14 CRA, with an early warning within 24 hours via ENISA's single reporting platform.
ISO/IEC 27001 ISO/IEC 27001 is the internationally leading standard for an information security management system (ISMS). It describes a risk-based, process-oriented framework to systematically plan, implement, review and improve information security. Read in glossary: Control A.8.8, management of technical vulnerabilities: assess relevance to your systems, plan remediation and keep evidence.

Description

Adobe Flash Player 21.0.0.226 and earlier allows remote attackers to execute arbitrary code via unspecified vectors, as exploited in the wild in May 2016.

Source: cvelistv5, NVD (NIST), CISA KEV Catalog, CVE.org (MITRE)

Affected products

The following versions are affected. Older releases of the same product line are also vulnerable unless stated otherwise.

Affected products
		Affected versions	Fixed in
adobe	flash_player	`≤ 21.0.0.226`	—

Vendors and products

Affected operating systems

Affected operating systems

Linux	redhat	enterprise_linux_desktop	`5.0`
Linux	redhat	enterprise_linux_desktop	`6.0`
Linux	redhat	enterprise_linux_server	`5.0`
Linux	redhat	enterprise_linux_server	`6.0`
Linux	redhat	enterprise_linux_server_from_rhui	`5.0`
Linux	redhat	enterprise_linux_server_from_rhui	`6.0`
Linux	redhat	enterprise_linux_workstation	`5.0`
Linux	redhat	enterprise_linux_workstation	`6.0`
Linux	opensuse	evergreen	`11.4`
Linux	suse	linux_enterprise_desktop	`12`
Linux	suse	linux_enterprise_workstation_extension	`12`
Linux	opensuse	opensuse	`13.1`
Linux	opensuse	opensuse	`13.2`

Public exploit references

Publicly reported proof-of-concepts, exploit modules and detection templates for this vulnerability. NEOSEC links to the original sources only and does not provide any exploit code.

Public exploit references

CISA KEV Catalog	CISA Known Exploited Vulnerability (opens in a new tab)cisa.gov	actively exploited	03.03.2022
Exploit-DB	EDB-ID 46339 (opens in a new tab)exploit-db.com	PoC (publicly reported)reported, not verified	—

References & sources

security.gentoo.orgGLSA-201606-08Vendor advisory, x_refsource_GENTOO
lists.opensuse.orgopenSUSE-SU-2016:1309Vendor advisory, x_refsource_SUSE
lists.opensuse.orgSUSE-SU-2016:1305Vendor advisory, x_refsource_SUSE
securitytracker.com1035826Vulnerability database, x_refsource_SECTRACK
exploit-db.com46339Exploit, x_refsource_EXPLOIT-DB
lists.opensuse.orgopenSUSE-SU-2016:1306Vendor advisory, x_refsource_SUSE
lists.opensuse.orgopenSUSE-SU-2016:1308Vendor advisory, x_refsource_SUSE
helpx.adobe.comsecurity/products/flash-player/apsb16-15.htmlx_refsource_CONFIRM
securityfocus.com90505Vulnerability database, x_refsource_BID
helpx.adobe.comsecurity/products/flash-player/apsa16-02.htmlx_refsource_CONFIRM
rhn.redhat.comRHSA-2016:1079Vendor advisory, x_refsource_REDHAT
cisa.govknown-exploited-vulnerabilities-catalog?field_cve=CVE-2016-4117government-resource
github.comcisagov/vulnrichment/issues/196Issue tracking

Changes to this CVE

Who changed this CVE and when: NVD (analysis, affected products, CVSS), the CVE publisher (CNA) and additional providers such as CISA (ADP).

10.09.2026Record modifiedAdobe

New references:

and 7 more references

Show 33 original changes

Individual changes of this event as published by NVD
Type	Action	Before	After
Reference	added	—	http://lists.opensuse.org/opensuse-security-announce/2016-05/msg00044.html
Reference	added	—	http://lists.opensuse.org/opensuse-security-announce/2016-05/msg00045.html
Reference	added	—	http://lists.opensuse.org/opensuse-security-announce/2016-05/msg00046.html
Reference	added	—	http://lists.opensuse.org/opensuse-security-announce/2016-05/msg00047.html
Reference	added	—	http://rhn.redhat.com/errata/RHSA-2016-1079.html
Reference	added	—	http://www.securityfocus.com/bid/90505
Reference	added	—	http://www.securitytracker.com/id/1035826
Reference	added	—	https://helpx.adobe.com/security/products/flash-player/apsa16-02.html
Reference	added	—	https://helpx.adobe.com/security/products/flash-player/apsb16-15.html
Reference	added	—	https://security.gentoo.org/glsa/201606-08
Reference	added	—	https://www.exploit-db.com/exploits/46339/
Reference	removed	http://lists.opensuse.org/opensuse-security-announce/2016-05/msg00044.html	—
Reference	removed	http://lists.opensuse.org/opensuse-security-announce/2016-05/msg00045.html	—
Reference	removed	http://lists.opensuse.org/opensuse-security-announce/2016-05/msg00046.html	—
Reference	removed	http://lists.opensuse.org/opensuse-security-announce/2016-05/msg00047.html	—
Reference	removed	http://rhn.redhat.com/errata/RHSA-2016-1079.html	—
Reference	removed	http://www.securityfocus.com/bid/90505	—
Reference	removed	http://www.securitytracker.com/id/1035826	—
Reference	removed	https://helpx.adobe.com/security/products/flash-player/apsa16-02.html	—
Reference	removed	https://helpx.adobe.com/security/products/flash-player/apsb16-15.html	—
Reference	removed	https://security.gentoo.org/glsa/201606-08	—
Reference	removed	https://www.exploit-db.com/exploits/46339/	—
Reference type	removed	http://lists.opensuse.org/opensuse-security-announce/2016-05/msg00044.html Types: Mailing List, Third Party Advisory	—
Reference type	removed	http://lists.opensuse.org/opensuse-security-announce/2016-05/msg00045.html Types: Mailing List, Third Party Advisory	—
Reference type	removed	http://lists.opensuse.org/opensuse-security-announce/2016-05/msg00046.html Types: Mailing List, Third Party Advisory	—
Reference type	removed	http://lists.opensuse.org/opensuse-security-announce/2016-05/msg00047.html Types: Mailing List, Third Party Advisory	—
Reference type	removed	http://rhn.redhat.com/errata/RHSA-2016-1079.html Types: Third Party Advisory	—
Reference type	removed	http://www.securityfocus.com/bid/90505 Types: Broken Link, Third Party Advisory, VDB Entry	—
Reference type	removed	http://www.securitytracker.com/id/1035826 Types: Broken Link, Third Party Advisory, VDB Entry	—
Reference type	removed	https://helpx.adobe.com/security/products/flash-player/apsa16-02.html Types: Broken Link, Vendor Advisory	—
Reference type	removed	https://helpx.adobe.com/security/products/flash-player/apsb16-15.html Types: Broken Link	—
Reference type	removed	https://security.gentoo.org/glsa/201606-08 Types: Third Party Advisory	—
Reference type	removed	https://www.exploit-db.com/exploits/46339/ Types: Exploit, Third Party Advisory, VDB Entry	—

Source identifier: psirt@adobe.com

10.09.2026Record modifiedCISA ADP

CISA assessment (SSVC): exploitation: active, automatable: no

New references:

Show 7 original changes

Individual changes of this event as published by NVD
Type	Action	Before	After
Reference	added	—	https://github.com/cisagov/vulnrichment/issues/196
Reference	added	—	https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2016-4117
Reference	removed	https://github.com/cisagov/vulnrichment/issues/196	—
Reference	removed	https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2016-4117	—
Reference type	removed	https://github.com/cisagov/vulnrichment/issues/196 Types: Issue Tracking	—
Reference type	removed	https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2016-4117 Types: US Government Resource	—
SSVC assessment	changed	{"id":"CVE-2016-4117","role":"CISA Coordinator","options":[{"exploitation":"active"},{"automatable":"no"},{"technicalImpact":"total"}],"version":"2.0.3","timestamp":"2025-11-17T19:42:32.956896Z"}	{"id":"CVE-2016-4117","role":"CISA Coordinator","options":[{"exploitation":"active"},{"automatable":"no"},{"technicalImpact":"total"}],"version":"2.0.3","timestamp":"2021-02-03T00:00:00+00:00"}

Source identifier: 134c704f-9b21-4f2e-91b3-4a467353bcc0

10.09.2026Record modifiedCVE Program

New references:

and 7 more references

Show 33 original changes

Individual changes of this event as published by NVD
Type	Action	Before	After
Reference	added	—	http://lists.opensuse.org/opensuse-security-announce/2016-05/msg00044.html
Reference	added	—	http://lists.opensuse.org/opensuse-security-announce/2016-05/msg00045.html
Reference	added	—	http://lists.opensuse.org/opensuse-security-announce/2016-05/msg00046.html
Reference	added	—	http://lists.opensuse.org/opensuse-security-announce/2016-05/msg00047.html
Reference	added	—	http://rhn.redhat.com/errata/RHSA-2016-1079.html
Reference	added	—	http://www.securityfocus.com/bid/90505
Reference	added	—	http://www.securitytracker.com/id/1035826
Reference	added	—	https://helpx.adobe.com/security/products/flash-player/apsa16-02.html
Reference	added	—	https://helpx.adobe.com/security/products/flash-player/apsb16-15.html
Reference	added	—	https://security.gentoo.org/glsa/201606-08
Reference	added	—	https://www.exploit-db.com/exploits/46339/
Reference	removed	http://lists.opensuse.org/opensuse-security-announce/2016-05/msg00044.html	—
Reference	removed	http://lists.opensuse.org/opensuse-security-announce/2016-05/msg00045.html	—
Reference	removed	http://lists.opensuse.org/opensuse-security-announce/2016-05/msg00046.html	—
Reference	removed	http://lists.opensuse.org/opensuse-security-announce/2016-05/msg00047.html	—
Reference	removed	http://rhn.redhat.com/errata/RHSA-2016-1079.html	—
Reference	removed	http://www.securityfocus.com/bid/90505	—
Reference	removed	http://www.securitytracker.com/id/1035826	—
Reference	removed	https://helpx.adobe.com/security/products/flash-player/apsa16-02.html	—
Reference	removed	https://helpx.adobe.com/security/products/flash-player/apsb16-15.html	—
Reference	removed	https://security.gentoo.org/glsa/201606-08	—
Reference	removed	https://www.exploit-db.com/exploits/46339/	—
Reference type	removed	http://lists.opensuse.org/opensuse-security-announce/2016-05/msg00044.html Types: Mailing List, Third Party Advisory	—
Reference type	removed	http://lists.opensuse.org/opensuse-security-announce/2016-05/msg00045.html Types: Mailing List, Third Party Advisory	—
Reference type	removed	http://lists.opensuse.org/opensuse-security-announce/2016-05/msg00046.html Types: Mailing List, Third Party Advisory	—
Reference type	removed	http://lists.opensuse.org/opensuse-security-announce/2016-05/msg00047.html Types: Mailing List, Third Party Advisory	—
Reference type	removed	http://rhn.redhat.com/errata/RHSA-2016-1079.html Types: Third Party Advisory	—
Reference type	removed	http://www.securityfocus.com/bid/90505 Types: Broken Link, Third Party Advisory, VDB Entry	—
Reference type	removed	http://www.securitytracker.com/id/1035826 Types: Broken Link, Third Party Advisory, VDB Entry	—
Reference type	removed	https://helpx.adobe.com/security/products/flash-player/apsa16-02.html Types: Broken Link, Vendor Advisory	—
Reference type	removed	https://helpx.adobe.com/security/products/flash-player/apsb16-15.html Types: Broken Link	—
Reference type	removed	https://security.gentoo.org/glsa/201606-08 Types: Third Party Advisory	—
Reference type	removed	https://www.exploit-db.com/exploits/46339/ Types: Exploit, Third Party Advisory, VDB Entry	—

Source identifier: af854a3a-2127-422b-91ae-364da2661108

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What is affected, what to do

Metrics

Response and mitigation

Prioritisation rationale

Immediate response (0-24 h)

Mitigation layers

Detection rules

Detection rules

Classification under NIS2 and CRA

Description

Affected products

Vendors and products

Affected operating systems

Public exploit references

References & sources

Changes to this CVE