CVE-2021-3493
Actively exploited. CVE-2021-3493 is listed in the CISA Known Exploited Vulnerabilities catalog (added 2022-10-20) — exploitation has been observed in the wild, and US federal agencies are required to remediate it under BOD 22-01. Treat patching as urgent.
Public exploit code is available. Proof-of-concept or working exploit code for CVE-2021-3493 is indexed in Metasploit and GitHub PoC. Expect opportunistic scanning and exploitation attempts — prioritize remediation.
The overlayfs stacking file system in Linux kernel does not properly validate the application of file capabilities against user namespaces, which could lead to privilege escalation.
CSIRTS triage
- What
- The overlayfs stacking file system does not properly validate file capabilities, leading to privilege escalation.
- Who is affected
- Users of affected Linux kernel versions.
- Urgency
- Immediate action is required as the vulnerability is critical and actively exploited.
- Action
- Update to the latest Linux kernel version.
AI-assisted analysis generated from the source advisory — verify against the original.
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Exploitation outlook
- Exploitation confirmedAlready exploited in the wild (CISA KEV) — the prediction phase is over. Patch now. Riskier than 99% of all EPSS-scored CVEs.
Exploit availability
Public exploit or proof-of-concept code for CVE-2021-3493 is indexed in these free datasets. Available exploit code raises real-world risk independent of the CVSS score.
- MetasploitA Metasploit Framework module targets this CVE — weaponized, point-and-click exploitation.look it up ↗
- GitHub PoCPublic proof-of-concept repositories on GitHub reference this CVE.look it up ↗
Advisory coverage (1)
- criticalexploitedCVE-2021-3493: Linux Kernel Privilege Escalation Vulnerabilitycisa-kev · 2022-10-20
External references
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