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Actively exploited in the wild. This CVE is on the CISA Known Exploited Vulnerabilities list — treat remediation as urgent. Federal remediation due by 2 May 2022.
Linux KernelOperating system · Linux

CVE-2021-22600

HIGH · 7.0 CVSS v3.1 Published 2022-01-26
Fix available
A fix is available. Upgrade to 4.14.259 / 4.19.222 or later.
See remediation →
96/100
Remediation priority · Urgent
In the wild Zero-click Patch available

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 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

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 · moderate confidence

A double free vulnerability in the packet_set_ring() function in net/packet/af_packet.c allows local users to trigger the bug through crafted syscalls, potentially leading to privilege escalation or denial of service.

MitigationUpgrade the Linux kernel to a version beyond the affected releases, or rebuild/patch the kernel with the fix from commit ec6af094ea28f0f2dda1a6a33b14cd57e36a9755.

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:>= 4.14.175, < 4.14.259>= 4.19.114, < 4.19.222>= 5.4.29, < 5.4.168>= 5.5.14, < 5.10.88>= 5.11, < 5.15.11
Debian LinuxOperating system
Affected:= 9.0= 10.0
8300 FirmwareOperating system
Affected:all versions
8700 FirmwareOperating system
Affected:all versions
A400 FirmwareOperating system
Affected:all versions
C400 FirmwareOperating system
Affected:all versions
H410c FirmwareOperating system
Affected:all versions
H300s FirmwareOperating system
Affected:all versions

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
High
Privileges
Low
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/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 the running Linux kernel version
    Run 'uname -r' or 'cat /proc/version' to obtain the kernel version, then compare it against the affected ranges: 4.14.175-4.14.258, 4.19.114-4.19.221, 5.4.29-5.4.167, 5.5.14-5.10.87, 5.11-5.15.10
    Affected if The kernel version falls within any of the affected ranges listed
  2. Confirm the system is Debian 9 or 10
    Run 'cat /etc/debian_version' to identify the Debian release
    Affected if The system is running Debian 9.0 or 10.0, which ship kernels within the affected version ranges
  3. Check for NetApp firmware version on affected models
    For NetApp 8300, 8700, A400, C400, H410c, H300s systems, use the vendor-provided interface or CLI command to retrieve the firmware version
    Affected if The NetApp device is any firmware version of the listed models (all versions are affected)
  4. Verify packet socket functionality is available
    Check if AF_PACKET support is present by examining kernel config 'CONFIG_PACKET' or testing with 'grep -q packet /proc/modules && echo loaded' or attempting to create a packet socket with a test program
    Affected if The system has packet socket support (CONFIG_PACKET) enabled, which is required to trigger the vulnerable code path in packet_set_ring()

A system is affected if it runs a Linux kernel version within the listed ranges, or is a Debian 9/10 system, or is an affected NetApp model at any firmware version, and has packet socket functionality available.

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
Upgrade available Upgrade to 4.14.259 / 4.19.222 / 5.4.168 or later
Fixed in 4.14.2594.19.2225.4.168
Vendor patch git.kernel.org →
Interim mitigation

Upgrade the Linux kernel to a version beyond the affected releases, or rebuild/patch the kernel with the fix from commit ec6af094ea28f0f2dda1a6a33b14cd57e36a9755.

Recommended fix High confidence

Linux Kernel >= 4.14.259, >= 4.19.222, >= 5.4.168, or >= 5.10.88 depending on your branch; Debian 10 users should apply security updates or migrate to Debian 11

  1. Identify the currently running kernel version using 'uname -r'
  2. Check your distribution's available kernel packages (e.g., 'apt list --installed | grep linux-image' on Debian/Ubuntu, 'rpm -qa kernel' on RHEL/CentOS)
  3. Upgrade to a fixed kernel version: for 4.14.x series use >= 4.14.259, for 4.19.x use >= 4.19.222, for 5.4.x use >= 5.4.168, for 5.10.x use >= 5.10.88
  4. On Debian systems, apply Debian LTS updates or upgrade to Debian 11 (Bullseye) which includes fixed kernel 5.10
  5. Reboot the system to load the new kernel ('sudo reboot')
  6. Verify the fix by checking 'uname -r' shows a version >= the fixed version for your branch
  7. Confirm the vulnerability is patched by checking the kernel version against the af_packet.c fix commit ec6af094ea28f0f2dda1a6a33b14cd57e36a9755
Caveat Kernel upgrades may require rebooting production systems; ensure compatibility with custom kernel modules or drivers before upgrading

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

Fix this in Linux Kernel Exploited in the wild — priority engagement
  • Consultation2.0 h
  • Implementation4.0 h
  • Testing3.0 h
  • Review / QA2.0 h
11.0 hours of engineering $1,930
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Scan for this in your stack

Free · runs locally
dbcve dependency scanner

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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-2021-22600 in production — separate from our analysis above.

No notes yet

Be the first to add a field note for this CVE — a mitigation you’ve verified, a version caveat, or a link to a working fix. Sign in above to contribute.

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