{"id":"CVE-2026-97939","title":"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.…","summary":"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.…","severity":"medium","cvss":5.5,"cvssVector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H","cwe":["CWE-770"],"vendor":"Linux","product":"Linux","affected":["Linux >= f0ad0860d01e47a3ffd220564c5c653b3afbe962 < ec1c6140394ee87127479bc500a3158b125bf07a","Linux >= f0ad0860d01e47a3ffd220564c5c653b3afbe962 < 0264b3ee09b118fec8a5471b4ca288f8ab84722f","Linux >= f0ad0860d01e47a3ffd220564c5c653b3afbe962 < d0a2e2a4ee6bfe51e398bfb6921a7d0f4c26bc1c","Linux >= f0ad0860d01e47a3ffd220564c5c653b3afbe962 < b7ee18725f2292ab554aa96a101ae42d45f008bd","Linux 2.6.35"],"published":"2026-09-25","updated":"2026-10-03","sourceUpdated":"2026-10-03T11:18:19.503","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-97939","references":[{"url":"https://git.kernel.org/stable/c/0264b3ee09b118fec8a5471b4ca288f8ab84722f","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/b7ee18725f2292ab554aa96a101ae42d45f008bd","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/d0a2e2a4ee6bfe51e398bfb6921a7d0f4c26bc1c","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/ec1c6140394ee87127479bc500a3158b125bf07a","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-97939.json"},{"url":"https://access.redhat.com/security/cve/CVE-2026-97939"},{"url":"https://bugzilla.redhat.com/show_bug.cgi?id=2541143"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-97939"},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-97939"},{"url":"https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-97939.mbox"},{"url":"https://git.kernel.org/stable/c/21e0749e8ef272ac7e3eefe0fa488a5983f4b038"}],"tags":["nvd","cve.org","csaf","vex","red-hat"],"epss":0.00206,"epssPercentile":0.10581,"cvssSource":"vendor","ingestedAt":"2026-09-25T11:06:38.883Z","slug":"CVE-2026-97939","body":"## Overview\n\nIn 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\").\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.\n\n## Vendor advisories\n\n- **Red Hat VEX** · Moderate · affected: Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 6, Red Hat Enterprise Linux 7, Red Hat Enterprise Linux 8, Red Hat Enterprise Linux 9, Red Hat OpenShift Container Platform 4 · no fix planned: Red Hat Enterprise Linux 6, Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 7, Red Hat Enterprise Linux 8, … · updated 2026-10-17 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-97939.json)","depth":"sunlit","depthScore":30,"depthScoreParts":{"impact":30.3,"likelihood":0,"exploitation":0,"ransomware":0},"changes":[{"seq":213419,"id":"CVE-2026-97939","ts":1790754714346,"field":"cvss","old":null,"new":"5.5"},{"seq":213418,"id":"CVE-2026-97939","ts":1790754714346,"field":"severity","old":"none","new":"medium"}]}