# CVE-2026-64096: batman-adv: mcast: fix use-after-free in orig\_node RCU release

- 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
- Known exploited (CISA KEV): no
- Published: 2026-07-19 · Updated: 2026-08-05

## Affected

- Linux: version range not reported
- Linux: 3.15

## Description

In the Linux kernel, the following vulnerability has been resolved: batman-adv: mcast: fix use-after-free in orig_node RCU release batadv_mcast_purge_orig() removes entries from RCU-protected hlists but does not wait for an RCU grace period before returning. Concurrent RCU readers may still accesses references to those entries at the point of removal. RCU-protected readers trying to operate on entries like orig->mcast_want_all_ipv6_node will then access already freed memory. Fix this by moving batadv_mcast_purge_orig() to batadv_orig_node_release(), just before the call_rcu() invocation. This ensures RCU readers that were active at purge time have drained before the orig_node memory is reclaimed.

## What to do

- Check your stack: if you ship or depend on Linux kernel, no fixed version is listed yet; follow the vendor advisory per the references below.
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## 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/ff3a4487ead475e27b43280b8ee3d8464fe280e1
- https://git.kernel.org/stable/c/78a63fb2f7d5630d1c1f2859a20d4e4226863b41
- https://git.kernel.org/stable/c/ced48f55bac73f0822eae90509e51b42b4f646c8
- https://git.kernel.org/stable/c/70bcb678561f0fb58f33270fc73f12f3be72b878
- https://git.kernel.org/stable/c/aef897c9d2dd0d9339167fb82b62beff68d076cb
- https://git.kernel.org/stable/c/8a3707653ab658e082ccd992e92594e01b09a3fc
- https://git.kernel.org/stable/c/edfb1e094104a50f931553dc82ac59246569fd32
- https://git.kernel.org/stable/c/20c2d6a20ca936f5aaa6dd40f73f262ac45c87cc

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