CVE-2026-99064
cipso: adjust cached option offsets when removing CIPSO
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.
INFO
Published Date :
Oct. 23, 2026, 1:17 p.m.
Last Modified :
Oct. 23, 2026, 1:17 p.m.
Remotely Exploit :
No
Source :
416baaa9-dc9f-4396-8d5f-8c081fb06d67
Solution
- Update the Linux kernel.
- Apply the patch for cipso option handling.
- Adjust cached offsets for specific options.
- Ensure correct option parsing after removal.
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associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
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approaches employed by adversaries to exploit the CVE-2026-99064
weaknesses.
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New CVE Received by 416baaa9-dc9f-4396-8d5f-8c081fb06d67
Oct. 23, 2026
Action Type Old Value New Value Added 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. Added Affected New affected value received. <a href="https://github.com/CVEProject/cvelistV5/blob/main/cves/2026/99xxx/CVE-2026-99064.json">CVE-2026-99064</a> Added Reference https://git.kernel.org/stable/c/2200fe1d6148b78e1b8f00f4b2bd47760015077f Added Reference https://git.kernel.org/stable/c/6d25ffca055a77787c21a36b66c253f76239411b Added Reference https://git.kernel.org/stable/c/6e49d611a9cfbaac927b8fa80ebd4f6b1f37ada0 Added Reference https://git.kernel.org/stable/c/b965977126a90e01825814c859ba4788691eddd3