{"id":"CVE-2026-98099","state":"PUBLISHED","title":"ipv6: mcast: use rcu_assign_pointer() for __rcu list updates","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nipv6: mcast: use rcu_assign_pointer() for __rcu list updates\n\nSeveral places in net/ipv6/mcast.c update RCU-protected lists\n(np->ipv6_mc_list, idev->mc_list, idev->mc_tomb) using direct pointer\nassignments instead of rcu_assign_pointer():\n\n1. In __ipv6_dev_mc_dec(), unlinking a group from idev->mc_list did:\n       *map = ma->next;\n   without rcu_assign_pointer() while concurrent readers traverse\n   idev->mc_list locklessly under rcu_read_lock().\n2. In ipv6_sock_mc_drop() and __ipv6_sock_mc_close(), unlinking a group\n   from np->ipv6_mc_list directly assigned *lnk = mc_lst->next and\n   np->ipv6_mc_list = mc_lst->next without rcu_assign_pointer(), racing\n   with lockless readers in inet6_mc_check().\n3. In __ipv6_sock_mc_join(), mc_lst->next was initialized to\n   np->ipv6_mc_list via raw assignment before publishing mc_lst.\n4. In mld_del_delrec() and __ipv6_dev_mc_inc(), __rcu source pointers\n   passed into rcu_assign_pointer() lacked explicit dereference helpers.\n\nFix these by consistently using rcu_assign_pointer() along with\nmc_dereference() / sock_dereference().","publishedAt":"2026-09-25T10:24:28.929Z","updatedAt":"2026-10-21T12:54:29.854Z","severity":null,"assigner":"Linux","products":["Linux Linux"],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"456b61bca8ee324ab6c18b065e632c9a8c88aa39","status":"affected","lessThan":"0e3e3cec28c4d1bf29948da40b4e9e5d44f7852b","versionType":"git"},{"version":"456b61bca8ee324ab6c18b065e632c9a8c88aa39","status":"affected","lessThan":"49d7e1b456ba2f3ee08b3e264d999c09992cde8e","versionType":"git"},{"version":"456b61bca8ee324ab6c18b065e632c9a8c88aa39","status":"affected","lessThan":"afca229b39acc2590976b3e4f6e0fe76cededc60","versionType":"git"},{"version":"456b61bca8ee324ab6c18b065e632c9a8c88aa39","status":"affected","lessThan":"2e46b0c9fcf7e10b64ce1630b925f47918d1f7f6","versionType":"git"},{"version":"456b61bca8ee324ab6c18b065e632c9a8c88aa39","status":"affected","lessThan":"0c8f56c583c3250408367880c98e4d6fbc929315","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/ipv6/mcast.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"2.6.38","status":"affected"},{"version":"0","status":"unaffected","lessThan":"2.6.38","versionType":"semver"},{"version":"6.6.160","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.12.114","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.57","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.2.7","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/ipv6/mcast.c"]}],"references":["https://git.kernel.org/stable/c/0e3e3cec28c4d1bf29948da40b4e9e5d44f7852b","https://git.kernel.org/stable/c/49d7e1b456ba2f3ee08b3e264d999c09992cde8e","https://git.kernel.org/stable/c/afca229b39acc2590976b3e4f6e0fe76cededc60","https://git.kernel.org/stable/c/2e46b0c9fcf7e10b64ce1630b925f47918d1f7f6","https://git.kernel.org/stable/c/0c8f56c583c3250408367880c98e4d6fbc929315"],"weaknesses":[],"ingestedAt":"2026-10-29T20:13:43.249Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/98xxx/CVE-2026-98099.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-98099","state":"PUBLISHED","datePublished":"2026-09-25T10:24:28.929Z","dateUpdated":"2026-10-21T12:54:29.854Z","assignerShortName":"Linux","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateReserved":"2026-09-25T10:19:56.077Z"},"containers":{"cna":{"title":"ipv6: mcast: use rcu_assign_pointer() for __rcu list updates","descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nipv6: mcast: use rcu_assign_pointer() for __rcu list updates\n\nSeveral places in net/ipv6/mcast.c update RCU-protected lists\n(np->ipv6_mc_list, idev->mc_list, idev->mc_tomb) using direct pointer\nassignments instead of rcu_assign_pointer():\n\n1. In __ipv6_dev_mc_dec(), unlinking a group from idev->mc_list did:\n       *map = ma->next;\n   without rcu_assign_pointer() while concurrent readers traverse\n   idev->mc_list locklessly under rcu_read_lock().\n2. In ipv6_sock_mc_drop() and __ipv6_sock_mc_close(), unlinking a group\n   from np->ipv6_mc_list directly assigned *lnk = mc_lst->next and\n   np->ipv6_mc_list = mc_lst->next without rcu_assign_pointer(), racing\n   with lockless readers in inet6_mc_check().\n3. In __ipv6_sock_mc_join(), mc_lst->next was initialized to\n   np->ipv6_mc_list via raw assignment before publishing mc_lst.\n4. In mld_del_delrec() and __ipv6_dev_mc_inc(), __rcu source pointers\n   passed into rcu_assign_pointer() lacked explicit dereference helpers.\n\nFix these by consistently using rcu_assign_pointer() along with\nmc_dereference() / sock_dereference()."}],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"456b61bca8ee324ab6c18b065e632c9a8c88aa39","status":"affected","lessThan":"0e3e3cec28c4d1bf29948da40b4e9e5d44f7852b","versionType":"git"},{"version":"456b61bca8ee324ab6c18b065e632c9a8c88aa39","status":"affected","lessThan":"49d7e1b456ba2f3ee08b3e264d999c09992cde8e","versionType":"git"},{"version":"456b61bca8ee324ab6c18b065e632c9a8c88aa39","status":"affected","lessThan":"afca229b39acc2590976b3e4f6e0fe76cededc60","versionType":"git"},{"version":"456b61bca8ee324ab6c18b065e632c9a8c88aa39","status":"affected","lessThan":"2e46b0c9fcf7e10b64ce1630b925f47918d1f7f6","versionType":"git"},{"version":"456b61bca8ee324ab6c18b065e632c9a8c88aa39","status":"affected","lessThan":"0c8f56c583c3250408367880c98e4d6fbc929315","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/ipv6/mcast.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"2.6.38","status":"affected"},{"version":"0","status":"unaffected","lessThan":"2.6.38","versionType":"semver"},{"version":"6.6.160","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.12.114","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.57","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.2.7","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/ipv6/mcast.c"]}],"references":[{"url":"https://git.kernel.org/stable/c/0e3e3cec28c4d1bf29948da40b4e9e5d44f7852b"},{"url":"https://git.kernel.org/stable/c/49d7e1b456ba2f3ee08b3e264d999c09992cde8e"},{"url":"https://git.kernel.org/stable/c/afca229b39acc2590976b3e4f6e0fe76cededc60"},{"url":"https://git.kernel.org/stable/c/2e46b0c9fcf7e10b64ce1630b925f47918d1f7f6"},{"url":"https://git.kernel.org/stable/c/0c8f56c583c3250408367880c98e4d6fbc929315"}],"providerMetadata":{"shortName":"Linux","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateUpdated":"2026-10-21T12:54:29.854Z"},"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.38","versionEndExcluding":"6.6.160"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.38","versionEndExcluding":"6.12.114"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.38","versionEndExcluding":"6.18.57"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.38","versionEndExcluding":"7.2.7"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.38","versionEndExcluding":"7.3"}]}]}],"x_generator":{"engine":"bippy-1.2.0"}}}}}