CVE-2026-64422: Linux kernel · Integer Overflow
Source GCVE Database
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
- 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:HExploitation evidence
Disclosed: evidence found.
CVE published 25 Jul 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by 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
| Product | Affected | Fixed in |
|---|---|---|
| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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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
- nvd.nist.gov/vuln/detail/CVE-2026-64422 (opens in a new tab)
- git.kernel.org/stable/c/27ddf4486c7dbf5bdd393fa8bef6b67179796d98 (opens in a new tab)
- git.kernel.org/stable/c/782708ca1ea1f68b8cbb5ea3a7f5f18d0000efae (opens in a new tab)
- git.kernel.org/stable/c/99206ce2244f8a3ed64298d0667c9055845a5dc7 (opens in a new tab)
- git.kernel.org/stable/c/a094ac95d3b69adfa1676eb9c8eae6835d4f1671 (opens in a new tab)
- git.kernel.org/stable/c/bbae351c0f32f7c200249e4aa6561b2b419dcf69 (opens in a new tab)
- git.kernel.org/stable/c/e81f805824a8109504fce090641b17d135b48cd1 (opens in a new tab)
- git.kernel.org/stable/c/efb8763d7bbb40cff4cc55a6b62c3095a038149c (opens in a new tab)
- git.kernel.org/stable/c/f0d88a4cd03affff6c08adf6c63964e235aede43 (opens in a new tab)
- cert-portal.siemens.com/productcert/html/ssa-019113.html (opens in a new tab)