DaystoPatch

Linux kernelExploited incident

Linux kernel 'Copy Fail' AF_ALG authencesn page-cache write privilege escalation (CVE-2026-31431)

CVE-2026-31431High, CVSS 7.8In CISA's Known Exploited Vulnerabilities catalog since 1 May 2026

  • Exploited after a fix existed
FixedFixed for every supported version 8 days after the first public report.

Response

Silence
0h
First public report to first vendor statement
Exposure
0h
First public report to first fix
Follow-through
8d
First public report to a fix for every supported version
  • Vendor silent
  • Vendor statement, no fix
  • Fixed for some versions
  • Fixed when disclosed
  • Date only, no time of day

Timeline and evidence

Open a moment to see its source and archived quote.

  1. First public report

    CVE-2026-31431 record (CNA: Linux)CuratedQuote verified

    "datePublished":"2026-04-22T08:15:10.123Z"

    CVE title: 'crypto: algif_aead - Revert to operating out-of-place'. Xint Code's public write-up with a 732-byte root PoC followed on 2026-04-29.

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    sha256:ebb50f47044c7707…
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    5 more sources for this moment
    CVE.org record CVE-2026-31431ClaimedQuote verified22 Apr 2026, 08:15 UTC

    In the Linux kernel, the following vulnerability has been resolved:

    CVE record published.

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    Hacker NewsClaimedQuote not checked yet29 Apr 2026, 18:54 UTC

    place and remains vulnerable, or at least their CVE tracker shows it as such: https://security-tracker.debian.org/tracker/CVE-2026-31431

    Earliest third-party post we hold. An independent author on another platform posted within 48 hours. Used for unreviewed incidents only, never graded.

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    Hacker News hn
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    Mastodon postClaimedQuote not checked yet29 Apr 2026, 21:32 UTC

    qucik mitigation for the copy.fail linux privilage excalation in case you can't reboot your systems right now: Step 1: make sure the algif_aead module is not loaded -> lsmod | grep algif_aead Step

    Earliest third-party post we hold.

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    Mastodon post social
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    Bluesky postClaimedQuote not checked yet30 Apr 2026, 09:26 UTC

    CVE-2026-31431. 100% Reliable Linux LPE — no race, no per-distro offsets, page-cache write that bypasses on-disk file-integrity tools and crosses containers. Found by Xint Co

    Earliest third-party post we hold. An independent author on another platform posted within 48 hours. Used for unreviewed incidents only, never graded.

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    Bluesky post social
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    CISA KEV (CVE-2026-31431)ClaimedQuote verified1 May 2026

    Linux Kernel Incorrect Resource Transfer Between Spheres Vulnerability

    Added to CISA's KEV catalog on 2026-05-01.

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    sha256:ef8fffede5c47200…
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  2. Vendor statement

    at disclosure

    CVE-2026-31431 record (CNA: Linux)CuratedQuote verified

    "datePublished":"2026-04-22T08:15:10.123Z"

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  3. First workaround

    No official mitigation found yet.

  4. First fix

    at disclosure

    kernel.org ChangeLog-6.18.22CuratedQuote verified

    Date: Sat Apr 11 14:26:52 2026 +0200

    Top entry of the Linux 6.18.22 ChangeLog is the release commit 'Linux 6.18.22' dated Sat Apr 11 14:26:52 2026 +0200 = 2026-04-11 12:26 UTC (commit author date). First fixed releases (6.18.22 and 6.19.12 on 2026-04-11; mainline 7.0 on 2026-04-12).

    Source
    kernel.org ChangeLog-6.18.22 vendor github
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  5. Fixed for all versions

    +8d

    kernel.org ChangeLog-5.10.254CuratedQuote verified

    Date: Thu Apr 30 11:25:29 2026 +0200

    Top entry of the Linux 5.10.254 ChangeLog is the release commit 'Linux 5.10.254' dated Thu Apr 30 11:25:29 2026 +0200 = 2026-04-30 09:25 UTC (commit author date). The older LTS backports (5.10.254, 5.15.204, 6.1.170, 6.6.137, 6.12.85) were tagged on 2026-04-30, one day after the public PoC; 5.10.254 was the last.

    Source
    kernel.org ChangeLog-5.10.254 vendor github
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Send this to your boss

No brief for this incident yet. We write one for every open incident and every critical bug exploited before a fix.

Affected products

  • Linux kernel 4.14 up to 5.10.253, 5.15.203, 6.1.169, 6.6.136, 6.12.84, 6.18.21, 6.19.11 (crypto: algif_aead)
How we built this timeline

Kernel moment model: vendor/world = the kernel CNA's CVE publication (first security-labelled public signal); First fix = first stable or mainline release containing the fix (R2: counts even though it precedes the CVE);

Fixed for all versions = the last of the stable/LTS releases the CVE record lists as fixed (R6: provided every then-supported affected line is listed). Release dates come from kernel.org ChangeLog files.

The fix is normally public in stable releases before the CVE is published, so exposure is zero. Downstream lag (Android, distributions) is not graded here.

Coordinated disclosure per Xint Code's timeline (reported 23 Mar 2026, 'Patches committed to mainline kernel' 1 Apr 2026, 'CVE-2026-31431 assigned' 22 Apr 2026, 'Public disclosure' 29 Apr 2026). Exploitation was reported after the fixes (KEV 1 May 2026).

Note the window: the public PoC (29 Apr 2026) preceded the 5.10-6.12 LTS backports (30 Apr 2026) by about a day. CVSS 7.8 from the kernel CNA record.

Related

No related incidents.

Linux kernel report card