{"schema":"threatline.record/2","record":{"id":"CVE-2026-98101","aliases":[],"summary":"ipv6: mcast: use copy-on-write RCU updates in ip6_mc_source()","details":"In the Linux kernel, the following vulnerability has been resolved:\n\nipv6: mcast: use copy-on-write RCU updates in ip6_mc_source()\n\npmc->sflist is read locklessly under rcu_read_lock() by\ninet6_mc_check() during packet reception in the UDP and RAW\nmulticast receive paths.\n\nip6_mc_source() mutated psl->sl_addr and psl->sl_count in-place\nwhen adding or removing a source filter. Additionally, when expanding\nthe filter buffer, newpsl was published via rcu_assign_pointer()\nbefore writing the new source into the array.\n\nBecause 16-byte struct in6_addr writes are not atomic and array\nshifting is not synchronized with RCU readers, concurrent readers in\ninet6_mc_check() could read torn IPv6 addresses or observe\nduplicated/missed source entries.\n\nFix this by switching ip6_mc_source() to copy-on-write RCU updates:\nallocate and fully populate newpsl before publishing it via\nrcu_assign_pointer(), and reclaim the old filter via kfree_rcu(),\nmatching ip6_mc_msfilter().\n\nAlso remove the now unused IP6_SFBLOCK macro.","categories":["Operating systems"],"product":"Linux","vendor":"Linux","ecosystem":null,"affected_ranges":[{"source":"CVE List","source_url":"https://www.cve.org/CVERecord?id=CVE-2026-98101","source_modified_at":"2026-10-19T09:13:53.770Z","fetched_at":"2026-10-23T18:45:31.882637Z","product":"Linux","vendor":"Linux","versions":[{"version":"882ba1f73c06831f2a21044ebd8864c485ac04f2","lessThan":"ac51321d3b2391860a935820ebcf4d8b9bb16a8a","status":"affected","versionType":"git"},{"version":"882ba1f73c06831f2a21044ebd8864c485ac04f2","lessThan":"dba00514bf668c26cb4900e9f0da84bf96bf065a","status":"affected","versionType":"git"},{"version":"882ba1f73c06831f2a21044ebd8864c485ac04f2","lessThan":"2c2091e2ee93049fc513ad1e6c99d8b6c809f467","status":"affected","versionType":"git"},{"version":"882ba1f73c06831f2a21044ebd8864c485ac04f2","lessThan":"20db91a052332ef5552bd2f651ffb9db911cf67b","status":"affected","versionType":"git"},{"version":"882ba1f73c06831f2a21044ebd8864c485ac04f2","lessThan":"c073d1b070f171d206b19c98d71739a97f15b3f1","status":"affected","versionType":"git"},{"version":"47c75e3923c8d562fea8daf0ccf31546a7bef0ea","status":"affected","versionType":"git"},{"version":"5.10.261","lessThan":"5.11","status":"affected","versionType":"semver"}],"defaultStatus":"unaffected"},{"source":"CVE List","source_url":"https://www.cve.org/CVERecord?id=CVE-2026-98101","source_modified_at":"2026-10-19T09:13:53.770Z","fetched_at":"2026-10-23T18:45:31.882637Z","product":"Linux","vendor":"Linux","versions":[{"version":"5.13","status":"affected"},{"version":"0","lessThan":"5.13","status":"unaffected","versionType":"semver"},{"version":"6.6.158","lessThanOrEqual":"6.6.*","status":"unaffected","versionType":"semver"},{"version":"6.12.112","lessThanOrEqual":"6.12.*","status":"unaffected","versionType":"semver"},{"version":"6.18.53","lessThanOrEqual":"6.18.*","status":"unaffected","versionType":"semver"},{"version":"7.2.7","lessThanOrEqual":"7.2.*","status":"unaffected","versionType":"semver"},{"version":"7.3","lessThanOrEqual":"*","status":"unaffected","versionType":"original_commit_for_fix"}],"defaultStatus":"affected"}],"fixed_versions":[{"source":"CVE List","source_url":"https://www.cve.org/CVERecord?id=CVE-2026-98101","source_modified_at":"2026-10-19T09:13:53.770Z","fetched_at":"2026-10-23T18:45:31.882637Z","package":{"name":"Linux","ecosystem":null},"version":"2c2091e2ee93049fc513ad1e6c99d8b6c809f467","basis":"first unaffected version stated in the CVE record"},{"source":"CVE List","source_url":"https://www.cve.org/CVERecord?id=CVE-2026-98101","source_modified_at":"2026-10-19T09:13:53.770Z","fetched_at":"2026-10-23T18:45:31.882637Z","package":{"name":"Linux","ecosystem":null},"version":"20db91a052332ef5552bd2f651ffb9db911cf67b","basis":"first unaffected version stated in the CVE record"},{"source":"CVE List","source_url":"https://www.cve.org/CVERecord?id=CVE-2026-98101","source_modified_at":"2026-10-19T09:13:53.770Z","fetched_at":"2026-10-23T18:45:31.882637Z","package":{"name":"Linux","ecosystem":null},"version":"5.11","basis":"first unaffected version stated in the CVE record"}],"cvss":null,"severity":null,"kev":{"listed":false},"epss":{"probability":0.00168,"percentile":0.05751,"score_date":"2026-10-23"},"published_at":"2026-09-25T10:35:52.731Z","modified_at":"2026-10-19T09:13:53.770Z","provenance":[{"source":"CVE List","url":"https://www.cve.org/CVERecord?id=CVE-2026-98101","fetched_at":"2026-10-23T18:45:31.882637Z","source_modified_at":"2026-10-19T09:13:53.770Z"},{"source":"EPSS","url":"https://api.first.org/data/v1/epss?cve=CVE-2026-98101","fetched_at":"2026-10-23T18:42:43.628194Z","source_modified_at":"2026-10-23"}],"sources":["CVE List","EPSS"],"references":[{"source":"CVE List","url":"https://git.kernel.org/stable/c/ac51321d3b2391860a935820ebcf4d8b9bb16a8a"},{"source":"CVE List","url":"https://git.kernel.org/stable/c/dba00514bf668c26cb4900e9f0da84bf96bf065a"},{"source":"CVE List","url":"https://git.kernel.org/stable/c/2c2091e2ee93049fc513ad1e6c99d8b6c809f467"},{"source":"CVE List","url":"https://git.kernel.org/stable/c/20db91a052332ef5552bd2f651ffb9db911cf67b"},{"source":"CVE List","url":"https://git.kernel.org/stable/c/c073d1b070f171d206b19c98d71739a97f15b3f1"}],"locations":[],"motoko_assessment":{"status":"requires_architecture_review","automatic_remediation":false},"cve_state":"PUBLISHED","classification":{"method":"product-first software-layer rules","rules_version":"2.1","matched_on":"product","confidence":"heuristic","reviewed":false},"change_timestamp":"2026-10-19T09:13:53.770Z","content_hash":"ab4f17ac46deedcfcffb50a43a802067f921493c5ebf11b442f0f8431963f169"}}