CVE-2026-99064: Linux kernel · cipso: adjust cached option offsets when removing CIPSO
Source GCVE Database
Not known to be exploited · CVSS 8.1 High · fixed in b965977126a90e01825814c859ba4788691eddd3 : patch Linux kernel soon.
Data as of 26 Oct 2026, 17:16 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– |
Description
In the Linux kernel, the following vulnerability has been resolved: cipso: adjust cached option offsets when removing CIPSO cipso_v4_skbuff_delattr() removes the CIPSO bytes but does not adjust cached offsets for options that follow them. For example, with a valid 10-byte CIPSO option followed by a seven-byte RR option, parsing records rr at offset 30. Removing CIPSO moves RR to offset 20, while the cached offset remains 30. Consumers such as ip_forward_options() and __ip_options_echo() then access the wrong bytes; the latter may interpret packet data as the option length and copy it into fixed-size option storage. Mirror cipso_v4_delopt() and subtract cipso_len from the srr, rr, ts and router_alert offsets when they follow CIPSO. cipso_len is the distance the first memmove() shifts those options. The later header move and network-header reset relocate the bytes and their offset base together.
References
- nvd.nist.gov/vuln/detail/CVE-2026-99064 (opens in a new tab)
- git.kernel.org/stable/c/2200fe1d6148b78e1b8f00f4b2bd47760015077f (opens in a new tab)
- git.kernel.org/stable/c/6d25ffca055a77787c21a36b66c253f76239411b (opens in a new tab)
- git.kernel.org/stable/c/6e49d611a9cfbaac927b8fa80ebd4f6b1f37ada0 (opens in a new tab)
- git.kernel.org/stable/c/b965977126a90e01825814c859ba4788691eddd3 (opens in a new tab)