Microsoft Windows Adobe Type Manager Library Remote Code Execution Vulnerability (CVE-2015-2426)
Published In CISA KEV since Sources: CVE.org
What is affected, what to do
Buffer underflow in atmfd.dll in the Windows Adobe Type Manager Library in Microsoft Windows Vista SP2, Windows Server 2008 SP2 and R2 SP1, Windows 7 SP1, Windows 8, Windows 8.1, Windows Server 2012 Gold and R2, and Windows RT Gold and 8.1 allows remote attackers to execute arbitrary code via a crafted OpenType font, aka "OpenType Font Driver Vulnerability."
The vulnerability is being actively exploited; treat it as a priority. 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
- Microsoft Windows Server 2008
eq r2..r2 - Microsoft Windows Server 2012
eq r2..r2
- Microsoft Windows Server 2008
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Metrics
8.8
Priority
XIEM Effective CVSS: highest available CVSS rating from NVD and vendor data.
Source: Vendor (CNA), CVSS v3
8.8
CVSS v3
Severity High on the scale from 0 to 10.
Source: CVE.org
86.6 %
EPSS score
High — model estimates ≥ 50% chance of real-world exploitation within 30 days.
Source: FIRST EPSS, percentile 99.74
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- 223.58 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- 8.8 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- 8.8
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- 86.6 %
- 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- 99.74
- 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
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- CISA assessment (SSVC)
- Exploitation: active · not automatable · Technical impact: total
- Source: CISA Vulnrichment, as of 10 February 2025
CWE
CWE is a catalogue of typical weakness types in software and hardware — such as flawed input validation, unsafe memory handling or poor authentication. Where a CVE names a concrete vulnerability in a concrete product, a CWE describes the underlying class of defect.
Read in glossary- CWE-124
Response and mitigation
Why act now?
Prioritisation rationale
This flaw gives kernel-level code execution over the network with no authentication. The only requirement is user interaction, such as visiting a page or opening a document, which makes it a natural drive-by and spear-phishing component with very high exploitation likelihood. Exposure is low in a normally patched, modern estate: the fix has been available for years, and current Windows versions no longer parse fonts in the kernel. The real risk sits in EOL Windows still running in OT, medical or line-of-business environments, and those hosts should be isolated or hardened as a priority. CISA does not flag known ransomware use for this CVE.
Runbook step 1
Immediate response (0-24 h)
- Verify and close the patch gap: A vendor patch is available (Microsoft's 2015 security update for atmfd.dll). Look up the KB number in the vendor advisory, then use WSUS/SCCM/Intune compliance reporting to confirm the fixed atmfd.dll is present on every in-scope host. Any system patched normally since 2015 should already be covered.
- Inventory legacy hosts: Affected platforms are Vista SP2, Windows 7 SP1, 8/8.1, RT, Server 2008/2008 R2, Server 2012/2012 R2 and early Windows 10 builds. Most of these are end-of-life. Run a CMDB or EDR query on OS build to find every instance still in production, such as OT HMIs, terminal servers and kiosks.
- Isolate anything you cannot patch: Move unpatched or EOL hosts without ESU into a dedicated segment. Block web browsing, mail clients and Office document handling on them.
- Disable ATMFD where patching is impossible: Set
HKLM\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Windows\DisableATMFD(DWORD) =1via GPO and reboot. Confirm in the vendor advisory that this applies to your OS version. Side effect: Type 1/OpenType PostScript fonts will no longer render. - Prioritise terminal servers and jump hosts: Kernel-level code execution on a multi-user system compromises every session on it, so patch or harden these first.
Runbook step 2
Mitigation layers
- Network/proxy: Block web-font downloads (
.otf,.ttf,.woff,.woff2, MIMEfont/*,application/x-font-*) from uncategorised or newly registered domains at the secure web gateway, at least for the legacy segment. - Mail gateway: Quarantine font attachments and documents or PDFs with embedded fonts. For legacy-segment recipients, deliver documents only through CDR (content disarm and reconstruction).
- Endpoint hardening: On Windows 10, set the "Untrusted Font Blocking" GPO (
Computer Configuration > Administrative Templates > System > Mitigation Options) to "Block untrusted fonts and log events". Enforce browser sandboxing, and disable remote-font rendering by browser policy on legacy hosts. - IPS/IDS: Enable vendor signatures for OpenType Font Driver/atmfd exploits (Suricata ET or Snort Talos, FILE-OTHER/font categories) in blocking mode on both HTTP and SMTP.
- IAM/least privilege: The exploit yields kernel privileges, so least privilege will not stop the initial execution. Remove local admin rights anyway and enable Credential Guard or LSA protection to slow lateral movement.
- Retirement plan: Record EOL systems in the risk register and your NIS2 treatment plan with a decommissioning date. Compensating controls are not a permanent fix.
- Network/proxy: Block web-font downloads (
Runbook step 3
Detection rules
- Crash artefacts (System/Application log): EID 1001 (BugCheck/WER) or EID 41 referencing
atmfd.dllorwin32k.sysshortly after a browser or document session can indicate a failed exploit attempt. KQL:Event | where EventID == 1001 and RenderedDescription has "atmfd" - Privilege jump from a user process (Sysmon EID 1 / EID 4688): A browser or Office process spawns a child running at System integrity. Sigma shape:
ParentImage|endswith: [iexplore.exe, chrome.exe, firefox.exe, winword.exe, acrord32.exe]ANDIntegrityLevel: System. - Font files in temp paths (Sysmon EID 11):
.otf/.ttf/.fonfiles created under%TEMP%,INetCacheorAppDataby unusual processes, followed shortly by anomalous process activity. - Network (Zeek/proxy): Entries in Zeek
files.logor proxy logs withmime_typefont/*orapplication/vnd.ms-opentypedelivered from rare domains to legacy-segment IPs. Follow up on any subsequent outbound connections that look like C2. - Untrusted Font Blocking log (Windows 10): Collect blocked-font events from
Microsoft-Windows-Win32k/Operationaland alert on spikes.
- Crash artefacts (System/Application log): EID 1001 (BugCheck/WER) or EID 41 referencing
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
Buffer underflow in atmfd.dll in the Windows Adobe Type Manager Library in Microsoft Windows Vista SP2, Windows Server 2008 SP2 and R2 SP1, Windows 7 SP1, Windows 8, Windows 8.1, Windows Server 2012 Gold and R2, and Windows RT Gold and 8.1 allows remote attackers to execute arbitrary code via a crafted OpenType font, aka "OpenType Font Driver Vulnerability."
Source: NVD (NIST), cvelistv5, CISA KEV Catalog, CVE.org (MITRE)
Vendors and products
- Microsoft Microsoft Windows 10
- Microsoft Microsoft Windows 7
- Microsoft Microsoft Windows 8 Professional Edition
- Microsoft Microsoft Windows 8.1
- Microsoft Microsoft Windows RT Gold
- Microsoft Microsoft Windows RT 8.1
- Microsoft Microsoft Windows Server 2008
- Microsoft Microsoft Windows Server 2012
- Microsoft Microsoft Windows Vista Gold on X64
Affected operating systems
| Windows | microsoft | windows_10 | — |
| Windows | microsoft | windows_7 | — |
| Windows | microsoft | windows_8 | — |
| Windows | microsoft | windows_8.1 | — |
| Windows | microsoft | windows_rt | — |
| Windows | microsoft | windows_rt_8.1 | — |
| Windows | microsoft | windows_server_2008 | r2 |
| Windows | microsoft | windows_server_2008 | — |
| Windows | microsoft | windows_server_2012 | r2 |
| Windows | microsoft | windows_server_2012 | — |
| Windows | microsoft | windows_vista | — |
Weakness classes (CWE)
CWE-124Buffer Underwrite ('Buffer Underflow')
Base
The product writes to a buffer using an index or pointer that references a memory location prior to the beginning of the buffer.
Entry at MITRE CWE-124
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.
| CISA KEV Catalog | CISA Known Exploited Vulnerability (opens in a new tab)cisa.gov | actively exploited | |
| Exploit-DB | EDB-ID 38222 (opens in a new tab)exploit-db.com | PoC (publicly reported)reported, not verified | — |
References & sources
- securitytracker.com1032991Vulnerability database, x_refsource_SECTRACK, Third-party advisory, Vulnerability database
- kb.cert.orgVU#103336Third-party advisory, x_refsource_CERT-VN, Third-party advisory, US government resource
- blog.trendmicro.comtrendlabs-security-intelligence/a-look-at-the-open-type-font-ma…x_refsource_MISC, Exploit, Third-party advisory
- docs.microsoft.comMS15-078Vendor advisory, x_refsource_MS, Patch, Vendor advisory
- exploit-db.com38222Exploit, x_refsource_EXPLOIT-DB, Third-party advisory, Vulnerability database
- securityfocus.com75951Vulnerability database, x_refsource_BID, Third-party advisory, Vulnerability database
- cisa.govknown-exploited-vulnerabilities-catalog?field_cve=CVE-2015-2426government-resource, US government resource
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<a href="https://intel.neosec.eu/en/cve/CVE-2015-2426"><img src="https://intel.neosec.eu/badge/cve/CVE-2015-2426.svg?lang=en" alt="CVE-2015-2426 – NEOSEC Intel" height="20"></a>