{"id":"CVE-2026-98101","revision":"76f4e284abe848a39f4aa70e6a43606c","records":[{"revision":"76f4e284abe848a39f4aa70e6a43606c","observedAt":"2026-10-23T15:48:27.903+00:00","statement":{"source":"cve-program","id":"CVE-2026-98101","aliases":[],"title":"ipv6: mcast: use copy-on-write RCU updates in ip6_mc_source()","description":"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.","state":0,"publishedAt":"2026-09-25T10:35:52.731+00:00","modifiedAt":"2026-10-19T09:13:53.77+00:00","affected":[{"ecosystem":"Vendor product","name":"Linux","ranges":[],"versions":[],"rawVersionEvidence":"{\n                    \"product\": \"Linux\",\n                    \"vendor\": \"Linux\",\n                    \"defaultStatus\": \"unaffected\",\n                    \"repo\": \"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\n                    \"programFiles\": [\n                        \"include/net/if_inet6.h\",\n                        \"net/ipv6/mcast.c\"\n                    ],\n                    \"versions\": [\n                        {\n                            \"version\": \"882ba1f73c06831f2a21044ebd8864c485ac04f2\",\n                            \"lessThan\": \"ac51321d3b2391860a935820ebcf4d8b9bb16a8a\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"882ba1f73c06831f2a21044ebd8864c485ac04f2\",\n                            \"lessThan\": \"dba00514bf668c26cb4900e9f0da84bf96bf065a\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"882ba1f73c06831f2a21044ebd8864c485ac04f2\",\n                            \"lessThan\": \"2c2091e2ee93049fc513ad1e6c99d8b6c809f467\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"882ba1f73c06831f2a21044ebd8864c485ac04f2\",\n                            \"lessThan\": \"20db91a052332ef5552bd2f651ffb9db911cf67b\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"882ba1f73c06831f2a21044ebd8864c485ac04f2\",\n                            \"lessThan\": \"c073d1b070f171d206b19c98d71739a97f15b3f1\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"47c75e3923c8d562fea8daf0ccf31546a7bef0ea\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"5.10.261\",\n                            \"lessThan\": \"5.11\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"semver\"\n                        }\n                    ]\n                }"},{"ecosystem":"Vendor product","name":"Linux","ranges":[],"versions":[],"rawVersionEvidence":"{\n                    \"product\": \"Linux\",\n                    \"vendor\": \"Linux\",\n                    \"defaultStatus\": \"affected\",\n                    \"repo\": \"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\n                    \"programFiles\": [\n                        \"include/net/if_inet6.h\",\n                        \"net/ipv6/mcast.c\"\n                    ],\n                    \"versions\": [\n                        {\n                            \"version\": \"5.13\",\n                            \"status\": \"affected\"\n                        },\n                        {\n                            \"version\": \"0\",\n                            \"lessThan\": \"5.13\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"6.6.158\",\n                            \"lessThanOrEqual\": \"6.6.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"6.12.112\",\n                            \"lessThanOrEqual\": \"6.12.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"6.18.53\",\n                            \"lessThanOrEqual\": \"6.18.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"7.2.7\",\n                            \"lessThanOrEqual\": \"7.2.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"7.3\",\n                            \"lessThanOrEqual\": \"*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"original_commit_for_fix\"\n                        }\n                    ]\n                }"}],"metrics":[],"references":["https://git.kernel.org/stable/c/ac51321d3b2391860a935820ebcf4d8b9bb16a8a","https://git.kernel.org/stable/c/dba00514bf668c26cb4900e9f0da84bf96bf065a","https://git.kernel.org/stable/c/2c2091e2ee93049fc513ad1e6c99d8b6c809f467","https://git.kernel.org/stable/c/20db91a052332ef5552bd2f651ffb9db911cf67b","https://git.kernel.org/stable/c/c073d1b070f171d206b19c98d71739a97f15b3f1"],"sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-98101","license":"CVE Program Terms of Use","key":"cve-program:CVE-2026-98101","identifiers":["CVE-2026-98101"]},"retained":false,"historicalAffected":[]}],"coverage":[]}