CVE-2026-64047: Linux kernel · Integer Underflow
Affects Linux kernelSource CVE Database V5
Not known to be exploited · CVSS 9.8 Critical · fixed in eca989eab4b2599dcb02f72140a7c08f08838520 : patch Linux kernel as a priority.
Data as of 26 Oct 2026, 15:59 UTC
- EPSS
- 0.5% chance of exploitation in 30 days – higher than 43% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
- CISA SSVC
- Exploitation
- No evidence of active exploitation and no public proof of concept
- Automatable
- Attackers can reliably automate steps 1–4 of the kill chain
- Technical impact
- Total control over the software or total information disclosure
CISA SSVC assessment, 2026-10-16.
- Patch
- Available – fixed in eca989eab4b2599dcb02f72140a7c08f08838520, 285943c6e7ca309bbea84b253745154241d9788a, 84158c2997159df4a0d70cd9c46774512d32a522 +6
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:HExploitation evidence
Disclosed: evidence found.
CVE published 19 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
|
| LinuxLinux | Affected
| Fixed in– |
Description
In the Linux kernel, the following vulnerability has been resolved: net: tls: fix off-by-one in sg_chain entry count for wrapped sk_msg ring When an sk_msg scatterlist ring wraps (sg.end < sg.start), tls_push_record() chains the tail portion of the ring to the head using sg_chain(). An extra entry in the sg array is reserved for this: struct sk_msg_sg { [...] /* The extra two elements: * 1) used for chaining the front and sections when the list becomes * partitioned (e.g. end < start). The crypto APIs require the * chaining; * 2) to chain tailer SG entries after the message. */ struct scatterlist data[MAX_MSG_FRAGS + 2]; The current code uses MAX_SKB_FRAGS + 1 as the ring size: sg_chain(&msg_pl->sg.data[msg_pl->sg.start], MAX_SKB_FRAGS - msg_pl->sg.start + 1, msg_pl->sg.data); This places the chain pointer at sg_chain(data[start], (MAX_SKB_FRAGS - msg_start + 1) .. = &data[start] + (MAX_SKB_FRAGS - msg_start + 1) - 1 = data[start + (MAX_SKB_FRAGS - start + 1) - 1] = data[MAX_SKB_FRAGS] instead of the true last entry. This is likely due to a "race" of the commit under Fixes landing close to commit 031097d9e079 ("bpf: sk_msg, zap ingress queue on psock down") Convert to ARRAY_SIZE and drop the data[start] / - start (as suggested by Sabrina).
References
- git.kernel.org/stable/c/73963a375885d5ccb7def39fd0b4f542e0f343dd (opens in a new tab)
- git.kernel.org/stable/c/47110c3a9ac247b688657337f5981efcfcb240dc (opens in a new tab)
- git.kernel.org/stable/c/84158c2997159df4a0d70cd9c46774512d32a522 (opens in a new tab)
- git.kernel.org/stable/c/131ef12057d92b77b636321b7849c69222405a97 (opens in a new tab)
- git.kernel.org/stable/c/66339b71f105e6f83e0da3b9583d95077534fe1d (opens in a new tab)
- git.kernel.org/stable/c/eca989eab4b2599dcb02f72140a7c08f08838520 (opens in a new tab)
- git.kernel.org/stable/c/2fb0dc7e0099686c4e9d2732745d8a31b18c3628 (opens in a new tab)
- git.kernel.org/stable/c/285943c6e7ca309bbea84b253745154241d9788a (opens in a new tab)