{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-98101","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","state":"PUBLISHED","assignerShortName":"Linux","dateReserved":"2026-09-25T10:25:14.315Z","datePublished":"2026-09-25T10:35:52.731Z","dateUpdated":"2026-10-03T11:02:23.528Z"},"containers":{"cna":{"providerMetadata":{"orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux","dateUpdated":"2026-10-03T11:02:23.528Z"},"descriptions":[{"lang":"en","value":"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."}],"affected":[{"product":"Linux","vendor":"Linux","defaultStatus":"unaffected","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["include/net/if_inet6.h","net/ipv6/mcast.c"],"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"}]},{"product":"Linux","vendor":"Linux","defaultStatus":"affected","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["include/net/if_inet6.h","net/ipv6/mcast.c"],"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-rc2","lessThanOrEqual":"*","status":"unaffected","versionType":"original_commit_for_fix"}]}],"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.13","versionEndExcluding":"6.6.158"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.13","versionEndExcluding":"6.12.112"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.13","versionEndExcluding":"6.18.53"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.13","versionEndExcluding":"7.2.7"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.13","versionEndExcluding":"7.3-rc2"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.10.261"}]}]}],"references":[{"url":"https://git.kernel.org/stable/c/ac51321d3b2391860a935820ebcf4d8b9bb16a8a"},{"url":"https://git.kernel.org/stable/c/dba00514bf668c26cb4900e9f0da84bf96bf065a"},{"url":"https://git.kernel.org/stable/c/2c2091e2ee93049fc513ad1e6c99d8b6c809f467"},{"url":"https://git.kernel.org/stable/c/20db91a052332ef5552bd2f651ffb9db911cf67b"},{"url":"https://git.kernel.org/stable/c/c073d1b070f171d206b19c98d71739a97f15b3f1"}],"title":"ipv6: mcast: use copy-on-write RCU updates in ip6_mc_source()","x_generator":{"engine":"bippy-1.2.0"}}}}