{"id":"CVE-2026-97939","summary":"ipmr: account multicast table and route memory","details":"In the Linux kernel, the following vulnerability has been resolved:\n\nipmr: account multicast table and route memory\n\nA netadmin in a user+net namespace can create many IPv4 and IPv6\nmulticast routing tables with MRT_TABLE and MRT6_TABLE. Each unseen\nid allocates an mr_table via the shared mr_table_alloc(), links it\ninto the per-net list, and leaves it until netns teardown. Those\nobjects were not charged to memcg, so the host unreclaimable slab\ngrows with the table count.\n\nAccount mr_table allocations with GFP_KERNEL_ACCOUNT and mark the\nIPv4/IPv6 MFC caches SLAB_ACCOUNT. This matches the established\nhandling of IP addresses, routes and alternate interface names.\n\nUnresolved MFC entries are still allocated from softIRQ with\nGFP_ATOMIC and are not charged. They expire after 10 seconds and are\nbounded by the socket receive queue; see commit 0079ad8e8dc3\n(\"ipmr: remove hard code cache_resolve_queue_len limit\").","modified":"2026-09-26T03:48:27.913084698Z","published":"2026-09-25T10:22:52.332Z","database_specific":{"cna_assigner":"Linux","osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/97xxx/CVE-2026-97939.json"},"references":[{"type":"PACKAGE","url":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"},{"type":"WEB","url":"https://git.kernel.org/stable/c/0264b3ee09b118fec8a5471b4ca288f8ab84722f"},{"type":"WEB","url":"https://git.kernel.org/stable/c/b7ee18725f2292ab554aa96a101ae42d45f008bd"},{"type":"WEB","url":"https://git.kernel.org/stable/c/d0a2e2a4ee6bfe51e398bfb6921a7d0f4c26bc1c"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/97xxx/CVE-2026-97939.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-97939"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"f0ad0860d01e47a3ffd220564c5c653b3afbe962"},{"fixed":"0264b3ee09b118fec8a5471b4ca288f8ab84722f"},{"fixed":"d0a2e2a4ee6bfe51e398bfb6921a7d0f4c26bc1c"},{"fixed":"b7ee18725f2292ab554aa96a101ae42d45f008bd"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-97939.json"}},{"package":{"name":"Kernel","ecosystem":"Linux"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"2.6.35"},{"fixed":"6.18.53"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.19.0"},{"fixed":"7.2.7"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-97939.json"}}],"schema_version":"1.9.0"}