CVE Catalog

CVE-2026-98026

Unknown
Published: Translated: NVD NIST

Summary

In the Linux kernel, the bridge multicast code improperly converts mglist to RCU. br_multicast_del_port_group unlists the port group without the proper RCU helper that preserves the next pointer and then immediately frees the port group without waiting for an RCU grace period; the only RCU walker of mglist, br_multicast_list_adjacent(), has always been buggy because mglist was never properly converted to RCU.

Risk Assessment

A use-after-free can occur during concurrent port group deletion and list traversal, risking memory corruption or a kernel crash.

Recommendation

Update the Linux kernel to a version with the fix that converts mglist to RCU and moves its initialization after eth_addr's.

Other vulnerabilities in Linux kernel

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Original NVD description (English source)

In the Linux kernel, the following vulnerability has been resolved: net: bridge: mcast: properly convert mglist to rcu Sashiko reported a bug [1] that br_multicast_del_port_group unlists the port group not using proper rcu helper that preserves the next pointer and after that immediately frees the port group without waiting for rcu grace period. The only rcu walker of mglist is br_multicast_list_adjacent() and it turns out that function has always been buggy because mglist was never properly converted to RCU. Fix it by converting it to rcu and moving its initialization after eth_addr's. Initializing p->next can use RCU_INIT_POINTER because we have a barrier from the hlist_add_head_rcu call later, besides we're initializing an unpublished structure anyway. [1] https://netdev-ai.bots.linux.dev/sashiko/#/patchset/20260826014200.362304-1-littleddfu%40gmail.com

Vulnerability data from NVD (NIST) · CISA KEV · EPSS