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Advisory severityMediumRed Hat Linux

Medium [CVE-2026-64096] fix use-after-free in orig_node RCU release

This medium-severity Red Hat Linux advisory covers CVE-2026-64096.

Aggregated and source-linked by VulniPulse. Data sources, validation and limitations.

CVE-2026-64096 Source published Source updated

VulniPulse record published Record updated

CVE-2026-64096
Affected products & platforms
Red Hat LinuxUnclassified
Open source advisory

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Summary

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. A flaw was found in the `batman-adv` (Better Approach To Mobile Ad-hoc Networking) multicast (mcast) module of the Linux kernel.

The `batadv_mcast_purge_orig()` function removes entries from RCU (Read-Copy-Update)-protected lists without ensuring that all active readers have finished accessing those entries.

This can lead to a use-after-free vulnerability, where concurrent operations may attempt to access memory that has already been released, potentially causing system instability or a denial of service. Red Hat severity: Moderate.

Weakness: CWE-825.

Affected versions

No affected-version range was extracted from the source record. The vendor advisory is authoritative. Check it before change work.

Official advisory · medium-confidence parse· fetched 6 days ago·verify at source

Fixed versions

No fixed release is recorded yet. That does not prove no patch exists. Confirm against the vendor advisory.

Official advisory · medium-confidence parse· fetched 6 days ago·verify at source

Mitigation

The source record does not include mitigation steps. That does not mean no fix exists. Read the vendor advisory below for the authoritative guidance.

Official advisory · medium-confidence parse· fetched 6 days ago·verify at source

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