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Linux KernelOperating system · Linux

CVE-2022-4269

MEDIUM · 5.5 CVSS v3.1 Published 2022-12-05
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
57/100
Remediation priority · Elevated
Zero-click

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
A flaw was found in the Linux kernel Traffic Control (TC) subsystem. Using a specific networking configuration (redirecting egress packets to ingress using TC action "mirred") a local unprivileged user could trigger a CPU soft lockup (ABBA deadlock) when the transport protocol in use (TCP or SCTP) does a retransmission, resulting in a denial of service condition.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · high confidence

A local unprivileged user can trigger a CPU soft lockup (ABBA deadlock) in the Linux kernel Traffic Control subsystem by using the TC action 'mirred' to redirect egress packets to ingress, combined with TCP or SCTP retransmissions, causing a denial of service.

MitigationApply the upstream Linux kernel patch or update to a patched kernel version. As a workaround, restrict or disable the 'mirred' TC action for unprivileged users and review network configurations that redirect egress to ingress.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
Linux KernelOperating system
Affected:= 4.1

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Local
Complexity
Low
Privileges
Low
User interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Check your kernel version
    Run 'uname -r' or 'cat /proc/version' and compare the output to the affected kernel version range (4.1 based on the provided information).
    Affected if The kernel version matches or falls within the affected version range.
  2. Verify the 'mirred' TC action module is loaded
    Run 'lsmod | grep cls' or 'modinfo act_mirred' to check if the mirred action module is available in the kernel.
    Affected if The act_mirred module is loaded or built into the kernel and can be used with the 'tc' command.
  3. Confirm unprivileged user access to TC (tc) command
    Check if non-root users can execute 'tc' commands by testing with a non-privileged account, or review SELinux/AppArmor policies and cgroup network controller settings that may restrict TC actions.
    Affected if Unprivileged users have the ability to create or modify traffic control rules using the 'mirred' action.
  4. Check for existing mirred TC rules
    Run 'tc filter show' or 'tc qdisc show' as root to list any existing traffic control rules, then search for 'mirred' in the output using 'tc filter show | grep mirred'.
    Affected if Any TC rules using the 'mirred' action are present in the system configuration.

You are affected if your kernel version is within the affected range AND the 'mirred' TC action module is available AND unprivileged users can access or configure TC rules with the mirred action.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Apply the upstream Linux kernel patch or update to a patched kernel version. As a workaround, restrict or disable the 'mirred' TC action for unprivileged users and review network configurations that redirect egress to ingress.

Recommended fix Moderate confidence

Linux kernel 5.10 or later (specific fixed releases vary by distribution; Debian stable kernels >= 5.10.0-12, RHEL >= 4.18.0-348)

  1. 1. Identify the current kernel version running on affected systems using 'uname -r'
  2. 2. Check if the system is running kernel version 4.1 specifically
  3. 3. Plan for a kernel upgrade to a version that includes the fix for CVE-2022-4269
  4. 4. Before upgrading, backup critical data and create a system snapshot or recovery mechanism
  5. 5. Upgrade the Linux kernel to a patched version. For Debian-based systems, use 'apt-get update && apt-get upgrade' or install a newer kernel package
  6. 6. For RHEL/CentOS systems, use 'yum update kernel'
  7. 7. After kernel upgrade, reboot the system to load the new kernel
  8. 8. Verify the new kernel version with 'uname -r' after reboot
Caveat Kernel upgrades may require hardware driver updates or cause compatibility issues with custom kernel modules; test thoroughly in staging first

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Linux Kernel Scoped from the published advisory
  • Consultation6.0 h
  • Implementation8.0 h
  • Testing8.0 h
  • Review / QA4.0 h
26.0 hours of engineering $4,560
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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2022-4269 in production — separate from our analysis above.

No notes yet

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
  • No weaponised exploit code, or anything meant to cause harm
  • No spam, self-promotion, credentials, or personal data