CVE Catalog

CVE-2026-98101

Unknown
Published: Translated: NVD NIST

Summary

In the Linux kernel, ip6_mc_source() in IPv6 multicast was changed to use copy-on-write RCU updates. Previously, modifications to the source filter list were done in-place, which could lead to torn IPv6 addresses or duplicated/missed entries for concurrent readers.

Risk Assessment

The vulnerability could cause incorrect IPv6 multicast behavior, including incorrect packet filtering, potentially disrupting applications using multicast.

Recommendation

Update the Linux kernel to a version containing the fix. Test IPv6 multicast applications after the update.

Other vulnerabilities in Linux kernel

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Original NVD description (English source)

In the Linux kernel, the following vulnerability has been resolved: ipv6: mcast: use copy-on-write RCU updates in ip6_mc_source() pmc->sflist is read locklessly under rcu_read_lock() by inet6_mc_check() during packet reception in the UDP and RAW multicast receive paths. ip6_mc_source() mutated psl->sl_addr and psl->sl_count in-place when adding or removing a source filter. Additionally, when expanding the filter buffer, newpsl was published via rcu_assign_pointer() before writing the new source into the array. Because 16-byte struct in6_addr writes are not atomic and array shifting is not synchronized with RCU readers, concurrent readers in inet6_mc_check() could read torn IPv6 addresses or observe duplicated/missed source entries. Fix this by switching ip6_mc_source() to copy-on-write RCU updates: allocate and fully populate newpsl before publishing it via rcu_assign_pointer(), and reclaim the old filter via kfree_rcu(), matching ip6_mc_msfilter(). Also remove the now unused IP6_SFBLOCK macro.

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