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Linux KernelOperating system · Linux

CVE-2026-53246

CRITICAL · 9.8 CVSS v3.1 Published 2026-06-25
Fix available
A fix is available. Upgrade to 6.18.36 / 7.0.13 or later.
See remediation →
100/100
Remediation priority · Urgent
Remotely reachable No privileges 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
In the Linux kernel, the following vulnerability has been resolved: sctp: validate cached peer INIT chunk length in COOKIE_ECHO processing When a listening SCTP server processes a COOKIE_ECHO chunk, the cached peer INIT chunk embedded after the cookie is parsed and its parameters are later walked by sctp_process_init() using sctp_walk_params(). However, the chunk header length of this cached INIT chunk was not validated against the remaining buffer in the COOKIE_ECHO payload. If the length field is inflated, the parameter walk can run beyond the actual received data, leading to out-of-bounds reads and potential memory corruption during later parameter handling (e.g. STATE_COOKIE processing and kmemdup() copies). Add a bounds check in sctp_unpack_cookie() to ensure the cached INIT chunk length does not exceed the available data in the COOKIE_ECHO buffer before it is used.

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

The SCTP implementation in the Linux kernel fails to validate the chunk header length of a cached peer INIT chunk embedded within COOKIE_ECHO messages. When processing COOKIE_ECHO, the cached INIT is parsed and its parameters are walked without verifying the length doesn't exceed the available buffer. An attacker can exploit this by providing an inflated length field to trigger out-of-bounds reads during parameter walking, leading to memory corruption during STATE_COOKIE processing and kmemdup() operations.

MitigationApply the kernel patch adding bounds validation in sctp_unpack_cookie() to reject COOKIE_ECHO chunks with oversized cached INIT lengths; if SCTP is not required, consider disabling the module as a temporary mitigation.

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:>= 2.6.12.1, < 6.18.36>= 6.19, < 7.0.13= 2.6.12= 7.1

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

CVSS:3.1/AV:N/AC:L/PR:N/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 kernel version
    Run 'uname -r' or 'cat /proc/version' and compare the version number to the affected ranges: < 6.18.36, >= 6.19 and < 7.0.13, = 7.1, or = 2.6.12
    Affected if The kernel version falls within any of the affected ranges (< 6.18.36, >= 6.19 to < 7.0.13, = 7.1, = 2.6.12)
  2. Verify SCTP module is loaded
    Run 'lsmod | grep sctp' to check if the SCTP kernel module is currently loaded
    Affected if The sctp module appears in the loaded modules list
  3. Check SCTP is built into kernel
    Check if SCTP support is compiled directly into the kernel by running 'cat /boot/config-$(uname -r) | grep CONFIG_IP_SCTP' or checking kernel configuration files
    Affected if CONFIG_IP_SCTP=y or CONFIG_IP_SCTP=m is set (y means built-in, m means module can be loaded)
  4. Confirm SCTP is actively in use
    Check for active SCTP associations or listeners: run 'ss -s' and look for SCTP lines, or check 'cat /proc/net/sctp/snmp' to see if SCTP traffic is being processed
    Affected if SCTP connections or traffic are present, indicating the SCTP stack is actively processing packets

The system is affected if it runs a vulnerable kernel version AND has SCTP enabled or loaded, since the flaw only triggers when processing COOKIE_ECHO messages through the SCTP protocol stack.

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 6.18.36 / 7.0.13 or later
Fixed in 6.18.367.0.13
Vendor patch git.kernel.org →
Interim mitigation

Apply the kernel patch adding bounds validation in sctp_unpack_cookie() to reject COOKIE_ECHO chunks with oversized cached INIT lengths; if SCTP is not required, consider disabling the module as a temporary mitigation.

Recommended fix High confidence

Linux Kernel 6.18.36 or later for the 6.x branch; Linux Kernel 7.0.13 or later for the 7.x branch

  1. Identify the currently running Linux kernel version using 'uname -r'
  2. Determine which branch your kernel version belongs to: if >= 2.6.12.1 and < 6.18.36, upgrade to 6.18.36 or later; if >= 6.19 and < 7.0.13, upgrade to 7.0.13 or later; if version 2.6.12, upgrade to a patched version; if version 7.1, upgrade to 7.1.x where the fix is included
  3. For distribution kernels (e.g., Ubuntu, RHEL, Debian), check for and apply the latest kernel security updates that address this CVE
  4. Reboot the system to load the patched kernel
  5. Verify the fix is applied by checking the kernel version and confirming the SCTP fix is present in the changelog or by examining the patched function sctp_unpack_cookie() in the kernel source
Caveat Kernel upgrades may require system reboot and could introduce compatibility issues with proprietary kernel modules or specific hardware drivers; ensure critical applications are tested on the new kernel before production deployment

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

Fix this in Linux Kernel Scoped from the published advisory
  • Consultation2.0 h
  • Implementation2.0 h
  • Testing3.0 h
  • Review / QA1.0 h
8.0 hours of engineering $1,390
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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-2026-53246 in production — separate from our analysis above.

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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