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Linux KernelOperating system · Linux

CVE-2026-31630

HIGH · 7.8 CVSS v3.1 Published 2026-04-24
Fix available
A fix is available. Upgrade to 6.18.23 / 6.19.13 or later.
See remediation →
80/100
Remediation priority · High
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: rxrpc: proc: size address buffers for %pISpc output The AF_RXRPC procfs helpers format local and remote socket addresses into fixed 50-byte stack buffers with "%pISpc". That is too small for the longest current-tree IPv6-with-port form the formatter can produce. In lib/vsprintf.c, the compressed IPv6 path uses a dotted-quad tail not only for v4mapped addresses, but also for ISATAP addresses via ipv6_addr_is_isatap(). As a result, a case such as [ffff:ffff:ffff:ffff:0:5efe:255.255.255.255]:65535 is possible with the current formatter. That is 50 visible characters, so 51 bytes including the trailing NUL, which does not fit in the existing char[50] buffers used by net/rxrpc/proc.c. Size the buffers from the formatter's maximum textual form and switch the call sites to scnprintf(). Changes since v1: - correct the changelog to cite the actual maximum current-tree case explicitly - frame the proof around the ISATAP formatting path instead of the earlier mapped-v4 example

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

A detailed technical summary for this CVE is being prepared.

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:>= 4.9.1, < 6.18.23>= 6.19, < 6.19.13= 4.9= 7.0

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
High
Integrity
High
Availability
High

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

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 6.18.23 / 6.19.13 or later
Fixed in 6.18.236.19.13
Vendor patch git.kernel.org →
Recommended fix High confidence

6.18.23 or later for 6.18.x branch; 6.19.13 or later for 6.19.x branch

  1. Identify the current running kernel version using `uname -r`
  2. Determine which stable kernel branch your current version belongs to (either 6.18.x or 6.19.x)
  3. For systems running kernel >= 4.9.1 and < 6.18.23: upgrade to kernel version 6.18.23 or later
  4. For systems running kernel >= 6.19 and < 6.19.13: upgrade to kernel version 6.19.13 or later
  5. For systems running kernel 4.9: upgrade to a version >= 6.18.23 (4.9 is very old and no longer maintained)
  6. Apply the kernel upgrade using your distribution's package manager (e.g., apt-get update && apt-get upgrade, yum update, dnf update)
  7. Reboot the system to load the new kernel
  8. Verify the fix is applied by checking the kernel version matches or exceeds the fixed versions above
Caveat Kernel upgrades may introduce compatibility issues with proprietary drivers or older software; test in staging environment before production deployment

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

We can perform the upgrade in your staging environment and verify nothing breaks — typical engagement from $1,950. Get the upgrade done

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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-2026-31630 in production — separate from our analysis above.

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What this is

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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
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