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VulnerabilityPublished Updated

CVE-2026-64422: Linux kernel · Integer Overflow

Source GCVE Database

0
Authoritative record:CVE-2026-64422· High 7.1

Not known to be exploited · CVSS 7.1 High · fixed in f0d88a4cd03affff6c08adf6c63964e235aede43 : patch Linux kernel soon.

Data as of 26 Oct 2026, 14:05 UTC

CVSS 3.1 base score
7.1High
How severe the flaw is on the 0–10 CVSS scale.
EPSS
0.1% chance of exploitation in 30 days – higher than 3% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch
Available – fixed in f0d88a4cd03affff6c08adf6c63964e235aede43, efb8763d7bbb40cff4cc55a6b62c3095a038149c, e81f805824a8109504fce090641b17d135b48cd1 +5
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 25 Jul 2026

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponised: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq Mirage: no evidence on record.

    No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.

What to do

Upgrade to a fixed release listed under Affected software.

Affected software

ProductAffectedFixed in
LinuxLinuxAffected
  • ≥ 91cc17c0e5e5ada156a8d5787a2509d263ea6bbf, < f0d88a4cd03affff6c08adf6c63964e235aede43
Fixed in
  • f0d88a4cd03affff6c08adf6c63964e235aede43
LinuxLinuxAffected
  • ≥ 91cc17c0e5e5ada156a8d5787a2509d263ea6bbf, < efb8763d7bbb40cff4cc55a6b62c3095a038149c
Fixed in
  • efb8763d7bbb40cff4cc55a6b62c3095a038149c
LinuxLinuxAffected
  • ≥ 91cc17c0e5e5ada156a8d5787a2509d263ea6bbf, < e81f805824a8109504fce090641b17d135b48cd1
Fixed in
  • e81f805824a8109504fce090641b17d135b48cd1
LinuxLinuxAffected
  • ≥ 91cc17c0e5e5ada156a8d5787a2509d263ea6bbf, < bbae351c0f32f7c200249e4aa6561b2b419dcf69
Fixed in
  • bbae351c0f32f7c200249e4aa6561b2b419dcf69
LinuxLinuxAffected
  • ≥ 91cc17c0e5e5ada156a8d5787a2509d263ea6bbf, < a094ac95d3b69adfa1676eb9c8eae6835d4f1671
Fixed in
  • a094ac95d3b69adfa1676eb9c8eae6835d4f1671
LinuxLinuxAffected
  • ≥ 91cc17c0e5e5ada156a8d5787a2509d263ea6bbf, < 782708ca1ea1f68b8cbb5ea3a7f5f18d0000efae
Fixed in
  • 782708ca1ea1f68b8cbb5ea3a7f5f18d0000efae

AI-suggested

A fix has been implemented in the Linux kernel to validate and reject invalid tcp_reordering sysctl values and to harden the tcp_mtu_probe() function against integer overflow. Users should apply the official kernel updates that include these patches.

Description

A high severity vulnerability (CVE-2026-64422) in the Linux kernel's IPv4 TCP stack allowed invalid negative values for the tcp_reordering sysctl to wrap and cause out-of-bounds reads during MTU probing. This was due to improper validation of sysctl writes and signed integer overflow in tcp_mtu_probe(). The issue has been resolved by adding validation to sysctl inputs and hardening the MTU probe size calculation.

References

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