CVE-2021-22600 — Linux kernel
HIGHCVE-2021-22600 is a high-severity (CVSS 7) CWE-415 vulnerability. It is in CISA's Known Exploited Vulnerabilities catalog (added 2022-04-11) — treat it as actively exploited and patch now. No vendor fix is recorded yet; mitigation options are listed below.
Exploitation Status
Actively exploited in the wild
- Confirmed by CISA's Known Exploited Vulnerabilities catalog on 2022-04-11. Federal agencies were required to remediate by 2022-05-02.
Exploitation and automatability from CISA (KEV catalog and SSVC triage) for CVE-2021-22600.
EPSS Exploitation Probability
Probability of exploitation in the next 30 days, from FIRST.org EPSS.
How urgent is this, really
CVE-2021-22600 by exploitation likelihood (EPSS) against impact (CVSS). Outside the shaded patch-first corner.
Where this sits among everything scored
Of 395,249 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Counts from FIRST.org, log-scaled.
Description
A double free bug in packet_set_ring() in net/packet/af_packet.c can be exploited by a local user through crafted syscalls to escalate privileges or deny service. We recommend upgrading kernel past the effected versions or rebuilding past ec6af094ea28f0f2dda1a6a33b14cd57e36a9755
Affected Products
debian linuxdebianlinux kernellinux8300 firmwarenetapp8700 firmwarenetappa400 firmwarenetappc400 firmwarenetappResearch use only. For defensive security, authorized penetration testing, and academic research only. Never execute exploit code against systems without explicit written authorization.
Detection & mitigation playbook
VulnerabilityDetect
Identify every host running the affected component and compare the installed build against the fixed version below — for source-built or distro-packaged software the version string, not a lockfile, is the source of truth (`dpkg -l`, `rpm -q`, or the binary's own `--version`).
Remediation status
No fixed release is recorded for CVE-2021-22600 yet. Track the upstream advisory, and apply the exposure-reduction steps below in the meantime.
Mitigate without a patch
Constrain what reaches the vulnerable code: limit the size and shape of untrusted input, isolate the affected component in a sandboxed or least-privileged process, and enable the platform's memory-safety mitigations (ASLR, stack protector, hardened allocator) so an out-of-bounds access is more likely to fail closed than to be exploitable.
Fixing This On Your OS
If you run this on a Linux distribution, patch through your package manager against the distro's own security advisory below — it tracks the exact backported fix for your release, which can ship on a different timeline (and sometimes a different severity) than the upstream project.
The Red Hat Enterprise Linux versions before 9 are not affected, because the commit that introduced the bug is not in currently supported versions of Red Hat Enterprise Linux. The commit that introduced this bug is: 61fad6816fc1 ("net/packet: tpacket_rcv: avoid a producer race condition").
Only users with access to the AF_PACKET socket can trigger this vulnerability. The mitigation would be to disable CAP_NET_RAW capability for the users that prevents access to AF_PACKET.Source: Red Hat security advisory for CVE-2021-22600 (CC BY 4.0)
Frequently Asked Questions
Is CVE-2021-22600 in your dependencies?
Find it across , including transitive dependencies.