CVE-2026-99064: Linux kernel · cipso: adjust cached option offsets when removing CIPSO
Affects Linux kernelSource CVE Database V5
Not known to be exploited · CVSS 8.1 High · fixed in b965977126a90e01825814c859ba4788691eddd3 : patch Linux kernel soon.
Data as of 26 Oct 2026, 14:18 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.
- Patch
- Available – fixed in b965977126a90e01825814c859ba4788691eddd3, 2200fe1d6148b78e1b8f00f4b2bd47760015077f, 6e49d611a9cfbaac927b8fa80ebd4f6b1f37ada0 +1
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:HExploitation evidence
Disclosed: evidence found.
CVE published 23 Oct 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 Linux kernel to b965977126a90e01825814c859ba4788691eddd3, 2200fe1d6148b78e1b8f00f4b2bd47760015077f, 6e49d611a9cfbaac927b8fa80ebd4f6b1f37ada0 or 6d25ffca055a77787c21a36b66c253f76239411b.
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– |
AI-suggested
A fix is available and has been applied in the Linux kernel versions identified by the fixed commit hashes. Users should update to a Linux kernel version that includes these fixes to remediate the vulnerability. No additional mitigation steps are indicated beyond applying the official patch.
Description
CVE-2026-99064 is a high-severity vulnerability in the Linux kernel's CIPSO implementation. The flaw occurs because cipso_v4_skbuff_delattr() removes CIPSO bytes without adjusting cached offsets for subsequent options. This causes consumers like ip_forward_options() and __ip_options_echo() to access incorrect bytes, potentially leading to improper interpretation and copying of packet data. The issue is fixed by adjusting cached option offsets after CIPSO removal to maintain correct parsing.
References
- git.kernel.org/stable/c/b965977126a90e01825814c859ba4788691eddd3 (opens in a new tab)
- git.kernel.org/stable/c/2200fe1d6148b78e1b8f00f4b2bd47760015077f (opens in a new tab)
- git.kernel.org/stable/c/6e49d611a9cfbaac927b8fa80ebd4f6b1f37ada0 (opens in a new tab)
- git.kernel.org/stable/c/6d25ffca055a77787c21a36b66c253f76239411b (opens in a new tab)