{"id":"CVE-2026-89950","state":"PUBLISHED","title":"batman-adv: mcast: linearize skbuff for packet generation","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nbatman-adv: mcast: linearize skbuff for packet generation\n\nbatadv_mcast_forw_packet() and batadv_mcast_forw_scrape() is not only\ncalled (indirectly) by the unsharing+linearizing batadv_recv_mcast_packet()\nhandler. When it is called (indirectly) by batadv_mcast_forw_mcsend() then\nit will be unshared but not linearized. The SKB_LINEAR_ASSERT() can\ntherefore cause a fatal BUG().\n\nThe linearization should happen during the expansion of the head because\nthe scrape function can be hit already during the initial\nbatadv_mcast_forw_mode() selection code:\n\n* batadv_interface_tx\n* batadv_mcast_forw_mode\n* batadv_mcast_forw_mode_by_count()\n* batadv_mcast_forw_push()\n  -> calls batadv_mcast_forw_expand_head() before everything else\n* batadv_mcast_forw_push_tvlvs()\n* batadv_mcast_forw_push_dests()\n* batadv_mcast_forw_push_adjust_padding()\n* batadv_mcast_forw_scrape()","publishedAt":"2026-09-16T10:32:35.485Z","updatedAt":"2026-10-19T08:55:24.361Z","severity":null,"assigner":"Linux","products":["Linux Linux"],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"90039133221e33964ccb4a536dad7eb0a372fff7","status":"affected","lessThan":"a9603e0a7cb5e0cddc6b23af153cf7daafc5c55e","versionType":"git"},{"version":"90039133221e33964ccb4a536dad7eb0a372fff7","status":"affected","lessThan":"c32e5e25c41201c8c3b796a4ab2c45103187091e","versionType":"git"},{"version":"90039133221e33964ccb4a536dad7eb0a372fff7","status":"affected","lessThan":"2879177539e3ece483a8e5406970373698e9a6c5","versionType":"git"},{"version":"90039133221e33964ccb4a536dad7eb0a372fff7","status":"affected","lessThan":"6a30a59e2660afd03c975f1b8eae6a2301161197","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/batman-adv/multicast_forw.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"6.8","status":"affected"},{"version":"0","status":"unaffected","lessThan":"6.8","versionType":"semver"},{"version":"6.12.110","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.51","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.2.5","status":"unaffected","lessThanOrEqual":"7.2.*","versionType":"semver"},{"version":"7.3","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/batman-adv/multicast_forw.c"]}],"references":["https://git.kernel.org/stable/c/a9603e0a7cb5e0cddc6b23af153cf7daafc5c55e","https://git.kernel.org/stable/c/c32e5e25c41201c8c3b796a4ab2c45103187091e","https://git.kernel.org/stable/c/2879177539e3ece483a8e5406970373698e9a6c5","https://git.kernel.org/stable/c/6a30a59e2660afd03c975f1b8eae6a2301161197"],"weaknesses":[],"ingestedAt":"2026-10-29T20:13:26.108Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/89xxx/CVE-2026-89950.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-89950","state":"PUBLISHED","datePublished":"2026-09-16T10:32:35.485Z","dateUpdated":"2026-10-19T08:55:24.361Z","assignerShortName":"Linux","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateReserved":"2026-09-11T19:38:34.777Z"},"containers":{"cna":{"title":"batman-adv: mcast: linearize skbuff for packet generation","descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nbatman-adv: mcast: linearize skbuff for packet generation\n\nbatadv_mcast_forw_packet() and batadv_mcast_forw_scrape() is not only\ncalled (indirectly) by the unsharing+linearizing batadv_recv_mcast_packet()\nhandler. When it is called (indirectly) by batadv_mcast_forw_mcsend() then\nit will be unshared but not linearized. The SKB_LINEAR_ASSERT() can\ntherefore cause a fatal BUG().\n\nThe linearization should happen during the expansion of the head because\nthe scrape function can be hit already during the initial\nbatadv_mcast_forw_mode() selection code:\n\n* batadv_interface_tx\n* batadv_mcast_forw_mode\n* batadv_mcast_forw_mode_by_count()\n* batadv_mcast_forw_push()\n  -> calls batadv_mcast_forw_expand_head() before everything else\n* batadv_mcast_forw_push_tvlvs()\n* batadv_mcast_forw_push_dests()\n* batadv_mcast_forw_push_adjust_padding()\n* batadv_mcast_forw_scrape()"}],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"90039133221e33964ccb4a536dad7eb0a372fff7","status":"affected","lessThan":"a9603e0a7cb5e0cddc6b23af153cf7daafc5c55e","versionType":"git"},{"version":"90039133221e33964ccb4a536dad7eb0a372fff7","status":"affected","lessThan":"c32e5e25c41201c8c3b796a4ab2c45103187091e","versionType":"git"},{"version":"90039133221e33964ccb4a536dad7eb0a372fff7","status":"affected","lessThan":"2879177539e3ece483a8e5406970373698e9a6c5","versionType":"git"},{"version":"90039133221e33964ccb4a536dad7eb0a372fff7","status":"affected","lessThan":"6a30a59e2660afd03c975f1b8eae6a2301161197","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/batman-adv/multicast_forw.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"6.8","status":"affected"},{"version":"0","status":"unaffected","lessThan":"6.8","versionType":"semver"},{"version":"6.12.110","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.51","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.2.5","status":"unaffected","lessThanOrEqual":"7.2.*","versionType":"semver"},{"version":"7.3","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/batman-adv/multicast_forw.c"]}],"references":[{"url":"https://git.kernel.org/stable/c/a9603e0a7cb5e0cddc6b23af153cf7daafc5c55e"},{"url":"https://git.kernel.org/stable/c/c32e5e25c41201c8c3b796a4ab2c45103187091e"},{"url":"https://git.kernel.org/stable/c/2879177539e3ece483a8e5406970373698e9a6c5"},{"url":"https://git.kernel.org/stable/c/6a30a59e2660afd03c975f1b8eae6a2301161197"}],"providerMetadata":{"shortName":"Linux","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateUpdated":"2026-10-19T08:55:24.361Z"},"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.8","versionEndExcluding":"6.12.110"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.8","versionEndExcluding":"6.18.51"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.8","versionEndExcluding":"7.2.5"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.8","versionEndExcluding":"7.3"}]}]}],"x_generator":{"engine":"bippy-1.2.0"}}}}}