CriticalCVE-2021-22986

    F5 BIG-IP and BIG-IQ Centralized Management iControl REST Remote Code Execution Vulnerability (CVE-2021-22986)

    Published In CISA KEV since Sources: SingCERT, CVE.org

    What is affected, what to do

    On BIG-IP versions 16.0.x before 16.0.1.1, 15.1.x before 15.1.2.1, 14.1.x before 14.1.4, 13.1.x before 13.1.3.6, and 12.1.x before 12.1.5.3 amd BIG-IQ 7.1.0.x before 7.1.0.3 and 7.0.0.x before 7.0.0.2, the iControl REST interface has an unauthenticated remote command execution vulnerability. Note: Software versions which have reached End of Software Development (EoSD) are not evaluated.

    The vulnerability is being actively exploited; treat it as a priority. CISA lists it as used in ransomware campaigns. Update big-ip_access_policy_manager to version 12.1.5.3, big-ip_advanced_firewall_manager to version 16.0.1.1, big-ip_advanced_web_application_firewall to version 16.0.1.1. Immediate actions, mitigation and detection rules are in the runbook below.

    Affected
    • BIG-IP; BIG-IQ eq BIG-IP 16.0.x before 16.0.1.1, 15.1.x before 15.1.2.1, 14.1.x before 14.1.4, 13.1.x before 13.1.3.6, 12.1.x before 12.1.5.3..BIG-IP 16.0.x before 16.0.1.1, 15.1.x before 15.1.2.1, 14.1.x before 14.1.4, 13.1.x before 13.1.3.6, 12.1.x before 12.1.5.3
    • BIG-IP; BIG-IQ eq BIG-IQ 7.1.0.x before 7.1.0.3, 7.0.0.x before 7.0.0.2..BIG-IQ 7.1.0.x before 7.1.0.3, 7.0.0.x before 7.0.0.2

    Not sure whether and how you are affected? Ask a question about this vulnerability

    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: SingCERT, CVE.org

    99.90 %

    EPSS score

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

    Source: FIRST EPSS, percentile 99.97

    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
    253.95 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 exploitedSource: ANSSI / CERT-FR How we classify
    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
    99.90 %
    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
    99.97
    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

    Response and mitigation

    Why act now?

    Prioritisation rationale

    This CVE is on KEV because it is unauthenticated, network-reachable and requires no user interaction; mass scanning started within days of disclosure and exploitation likelihood ranks among the highest observed. CISA flags active ransomware use — BIG-IP devices are prized initial-access targets since they sit at the perimeter, hold administrative credentials and enable lateral movement into internal networks. For NIS2-regulated organisations running F5 at the edge this is a P1 incident: verify external exposure of the management plane, patch or take the device offline within 24 hours, and run assume-breach forensics if the device has been exposed over the past months.

    1. Runbook step 1

      Immediate response (0-24 h)

      • Patch now: upgrade BIG-IP to 16.0.1.1, 15.1.2.1, 14.1.4, 13.1.3.6 or 12.1.5.3; BIG-IQ to 7.1.0.3 or 7.0.0.2 (F5 advisory K03009991). EoSD branches (e.g. 11.x) receive no fix — plan migration or disconnect.
      • Remove the management interface (TMUI/iControl REST) from the public internet immediately. Validate via external scan on ports 443/8443 of the management plane. Permit access only via a dedicated admin VLAN or jump host.
      • If patching within hours is impossible, apply the F5 workaround: restrict iControl REST on all Self-IPs with tmsh modify net self <SELFIP> allow-service none (or default) and limit tmsh modify sys httpd allow to trusted admin IPs. Simply disabling provision.restnode is NOT sufficient.
      • Rotate all local admin credentials (admin, root), API tokens, and associated keys/certificates on affected appliances. Treat as compromised given unauthenticated RCE and active ransomware use.
      • Forensic triage: preserve /var/log/restjavad.0.log, /var/log/restnoded/restnoded.log, /var/log/audit, /var/log/secure; hunt for POST requests to /mgmt/tm/util/bash and unexpected bash/id/whoami executions.

    2. Runbook step 2

      Mitigation layers

      • Network segmentation: management plane in its own VLAN, reachable only from PAW/bastion. Perimeter ACL drops inbound TCP/443 and TCP/8443 to any Self-IP carrying production traffic (Virtual Servers remain reachable, iControl REST does not).
      • WAF/IPS in front of BIG-IP: block POST /mgmt/tm/util/bash, POST /mgmt/shared/authn/login followed by bash payloads, and requests carrying X-F5-Auth-Token: without a prior legitimate authentication. Deploy Suricata/Snort signatures ET 2032990–2032994.
      • Hardening: enforce TLS client certificates on the management httpd; disable Basic Auth to iControl REST where feasible; restrict SSH on the management IP to key-only.
      • IAM/least-privilege: dedicated service accounts for F5 automation (Ansible, Terraform) with role-scoped rights; never use admin for automation.
      • Configuration safety: regular UCS backup exported to an external store (not just local) so a clean restore is possible after suspected compromise. Verify integrity via tmsh show sys software and hash comparison.
      • Egress filtering from the BIG-IP management IP: allow only NTP, DNS, F5 licensing endpoints, SIEM — any outbound shell/HTTP traffic is an IoC.

    3. Runbook step 3

      Detection rules

      • Access logs (/var/log/restjavad.0.log, Zeek http.log): POST requests to /mgmt/tm/util/bash, /mgmt/shared/authn/login, /mgmt/tm/access/bundle-install-tasks from external source IPs. Sigma shape: selection: cs-method: POST AND cs-uri-stem|contains: '/mgmt/tm/util/bash'.
      • Auth-bypass pattern: requests with Authorization: Basic YWRtaW46 (admin:) combined with an X-F5-Auth-Token header in the same session within seconds — the canonical CVE-2021-22986 exploit chain.
      • Process monitoring on the appliance: unexpected children of restjavad or restnoded (e.g. bash, curl, wget, python, nc). KQL shape (Linux EDR agent): DeviceProcessEvents | where InitiatingProcessFileName in ('restjavad','restnoded') and FileName in ('bash','sh','curl','wget','nc','python').
      • Filesystem IoCs: new files in /tmp, /var/tmp, /var/config/rest/downloads, especially executable scripts or webshells; auditd watches on /config/httpd/conf/httpd.conf and /etc/passwd.
      • Network telemetry: outbound connections from the BIG-IP management IP to non-whitelisted destinations, particularly reverse shells on 4444, 8080, 1337 or DNS tunnelling.

    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

    On BIG-IP versions 16.0.x before 16.0.1.1, 15.1.x before 15.1.2.1, 14.1.x before 14.1.4, 13.1.x before 13.1.3.6, and 12.1.x before 12.1.5.3 amd BIG-IQ 7.1.0.x before 7.1.0.3 and 7.0.0.x before 7.0.0.2, the iControl REST interface has an unauthenticated remote command execution vulnerability. Note: Software versions which have reached End of Software Development (EoSD) are not evaluated.

    Source: CSA/SingCERT, NVD (NIST), cvelistv5, CISA KEV Catalog

    Affected products

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

    Affected products
    Affected versionsFixed in
    —BIG-IP; BIG-IQ
    • BIG-IQ 7.1.0.x before 7.1.0.3, 7.0.0.x before 7.0.0.2
    • BIG-IP 16.0.x before 16.0.1.1, 15.1.x before 15.1.2.1, 14.1.x before 14.1.4, 13.1.x before 13.1.3.6, 12.1.x before 12.1.5.3
    • —
    • —
    f5big-ip_access_policy_manager
    • 12.1.0 – < 12.1.5.3
    • 14.1.0 – < 14.1.4
    • 16.0.0 – < 16.0.1.1
    • 13.1.0 – < 13.1.3.6
    • 15.1.0 – < 15.1.2.1
    • 12.1.5.3
    • 14.1.4
    • 16.0.1.1
    • 13.1.3.6
    • 15.1.2.1
    f5big-ip_advanced_firewall_manager
    • 16.0.0 – < 16.0.1.1
    • 12.1.0 – < 12.1.5.3
    • 14.1.0 – < 14.1.4
    • 13.1.0 – < 13.1.3.6
    • 15.1.0 – < 15.1.2.1
    • 16.0.1.1
    • 12.1.5.3
    • 14.1.4
    • 13.1.3.6
    • 15.1.2.1
    f5big-ip_advanced_web_application_firewall
    • 16.0.0 – < 16.0.1.1
    • 14.1.0 – < 14.1.4
    • 12.1.0 – < 12.1.5.3
    • 13.1.0 – < 13.1.3.6
    • 15.1.0 – < 15.1.2.1
    • 16.0.1.1
    • 14.1.4
    • 12.1.5.3
    • 13.1.3.6
    • 15.1.2.1
    f5big-ip_analytics
    • 12.1.0 – < 12.1.5.3
    • 15.1.0 – < 15.1.2.1
    • 13.1.0 – < 13.1.3.6
    • 14.1.0 – < 14.1.4
    • 16.0.0 – < 16.0.1.1
    • 12.1.5.3
    • 15.1.2.1
    • 13.1.3.6
    • 14.1.4
    • 16.0.1.1
    f5big-ip_application_acceleration_manager
    • 12.1.0 – < 12.1.5.3
    • 14.1.0 – < 14.1.4
    • 13.1.0 – < 13.1.3.6
    • 16.0.0 – < 16.0.1.1
    • 15.1.0 – < 15.1.2.1
    • 12.1.5.3
    • 14.1.4
    • 13.1.3.6
    • 16.0.1.1
    • 15.1.2.1
    f5big-ip_application_security_manager
    • 14.1.0 – < 14.1.4
    • 12.1.0 – < 12.1.5.3
    • 15.1.0 – < 15.1.2.1
    • 16.0.0 – < 16.0.1.1
    • 13.1.0 – < 13.1.3.6
    • 14.1.4
    • 12.1.5.3
    • 15.1.2.1
    • 16.0.1.1
    • 13.1.3.6
    f5big-ip_ddos_hybrid_defender
    • 14.1.0 – < 14.1.4
    • 16.0.0 – < 16.0.1.1
    • 15.1.0 – < 15.1.2.1
    • 12.1.0 – < 12.1.5.3
    • 13.1.0 – < 13.1.3.6
    • 14.1.4
    • 16.0.1.1
    • 15.1.2.1
    • 12.1.5.3
    • 13.1.3.6
    f5big-ip_domain_name_system
    • 16.0.0 – < 16.0.1.1
    • 15.1.0 – < 15.1.2.1
    • 14.1.0 – < 14.1.4
    • 13.1.0 – < 13.1.3.6
    • 12.1.0 – < 12.1.5.3
    • 16.0.1.1
    • 15.1.2.1
    • 14.1.4
    • 13.1.3.6
    • 12.1.5.3
    f5big-ip_fraud_protection_service
    • 15.1.0 – < 15.1.2.1
    • 16.0.0 – < 16.0.1.1
    • 12.1.0 – < 12.1.5.3
    • 13.1.0 – < 13.1.3.6
    • 14.1.0 – < 14.1.4
    • 15.1.2.1
    • 16.0.1.1
    • 12.1.5.3
    • 13.1.3.6
    • 14.1.4
    f5big-ip_global_traffic_manager
    • 14.1.0 – < 14.1.4
    • 14.1.4

    Vendors and products

    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 CatalogCISA Known Exploited Vulnerability (opens in a new tab)cisa.govactively exploited
    ANSSI / CERT-FRLicence Ouverte 2.0, as of CERTFR-2021-ALE-006 – [MàJ] Vulnérabilité dans F5 BIG-IP (clôturée 2021-04-15) (opens in a new tab)cert.cyber.gouv.fractively exploited
    Packet StormF5 iControl Server Side Request Forgery Remote Command Execution (opens in a new tab)packetstormsecurity.comPoC (publicly reported)reported, not verified—
    Packet StormF5 BIG IP 16.0.x Remote Code Execution (opens in a new tab)packetstormsecurity.comPoC (publicly reported)reported, not verified—

    References & sources

    • support.f5.comcsp/article/K03009991x_refsource_MISC, Vendor advisory
    • packetstormsecurity.comfiles/162059/F5-iControl-Server-Side-Request-Forgery-Remote-Com…x_refsource_MISC, Exploit, Third-party advisory, Vulnerability database
    • packetstormsecurity.comfiles/162066/F5-BIG-IP-16.0.x-Remote-Code-Execution.htmlx_refsource_MISC, Exploit, Third-party advisory, Vulnerability database
    • cisa.govknown-exploited-vulnerabilities-catalog?field_cve=CVE-2021-22986government-resource, US government resource
    • cert.cyber.gouv.frANSSI / CERT-FR: CERTFR-2021-ALE-006 – [MàJ] Vulnérabilité dans F5 BIG-IP (clôturée 2021-04-15)cert-fr
    Embed badge

    Show the severity and KEV status of this vulnerability on your site – with a link back here. The image is updated hourly.

    Badge preview for CVE-2021-22986
    <a href="https://intel.neosec.eu/en/cve/CVE-2021-22986"><img src="https://intel.neosec.eu/badge/cve/CVE-2021-22986.svg?lang=en" alt="CVE-2021-22986 – NEOSEC Intel" height="20"></a>