CVE-2026-97939
In the Linux kernel, the following vulnerability has been resolved: ipmr: account multicast table and route memory A netadmin in a user+net namespace can create many IPv4 and IPv6 multicast routing tables with MRT_TABLE and MRT6_TABLE. Each unseen id allocates an mr_table via the shared mr_table_alloc(), links it into the per-net list, and leaves it until netns teardown. Those objects were not charged to memcg, so the host unreclaimable slab grows with the table count. Account mr_table allocations with GFP_KERNEL_ACCOUNT and mark the IPv4/IPv6 MFC caches SLAB_ACCOUNT. This matches the established handling of IP addresses, routes and alternate interface names. Unresolved MFC entries are still allocated from softIRQ with GFP_ATOMIC and are not charged. They expire after 10 seconds and are bounded by the socket receive queue; see commit 0079ad8e8dc3 ("ipmr: remove hard code cache_resolve_queue_len limit").
Affected versions
Linux kernel versions
2.6.35
and later are affected. Fixed in
6.12.112,
6.18.53,
7.2.7,
7.3-rc3
and their respective stable series.
References
4 totalFrequently asked questions
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What is CVE-2026-97939?
CVE-2026-97939 is a unscored severity Linux kernel vulnerability . It affects Linux kernel versions from 2.6.35 onward and has been patched in 6.12.112, 6.18.53, 7.2.7 and others. CVE-2026-97939 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.
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Is there a patch available for CVE-2026-97939?
Yes. CVE-2026-97939 has been patched. Fixed versions include 6.12.112, 6.18.53, 7.2.7 and others. If you are running Linux kernel 2.6.35 or later up to the fix versions, apply the relevant patch for your kernel branch.
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Is CVE-2026-97939 actively exploited?
No. CVE-2026-97939 has not been confirmed as actively exploited. It is not listed in the CISA Known Exploited Vulnerabilities (KEV) catalog.