{"api_version":"1","generated_at":"2026-04-25T13:02:34+00:00","cve":"CVE-2026-31680","urls":{"html":"https://cve.report/CVE-2026-31680","api":"https://cve.report/api/cve/CVE-2026-31680.json","docs":"https://cve.report/api","cve_org":"https://www.cve.org/CVERecord?id=CVE-2026-31680","nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-31680"},"summary":{"title":"net: ipv6: flowlabel: defer exclusive option free until RCU teardown","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nnet: ipv6: flowlabel: defer exclusive option free until RCU teardown\n\n`ip6fl_seq_show()` walks the global flowlabel hash under the seq-file\nRCU read-side lock and prints `fl->opt->opt_nflen` when an option block\nis present.\n\nExclusive flowlabels currently free `fl->opt` as soon as `fl->users`\ndrops to zero in `fl_release()`. However, the surrounding\n`struct ip6_flowlabel` remains visible in the global hash table until\nlater garbage collection removes it and `fl_free_rcu()` finally tears it\ndown.\n\nA concurrent `/proc/net/ip6_flowlabel` reader can therefore race that\nearly `kfree()` and dereference freed option state, triggering a crash\nin `ip6fl_seq_show()`.\n\nFix this by keeping `fl->opt` alive until `fl_free_rcu()`. That matches\nthe lifetime already required for the enclosing flowlabel while readers\ncan still reach it under RCU.","state":"PUBLISHED","assigner":"Linux","published_at":"2026-04-25 09:16:01","updated_at":"2026-04-25 09:16:01"},"problem_types":[],"metrics":[],"references":[{"url":"https://git.kernel.org/stable/c/5a6b15f861b7c1304949e3350d23490a5fe429fd","name":"https://git.kernel.org/stable/c/5a6b15f861b7c1304949e3350d23490a5fe429fd","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/6c7fbdb8ffde6413640de7cfbd7c976c353e89f8","name":"https://git.kernel.org/stable/c/6c7fbdb8ffde6413640de7cfbd7c976c353e89f8","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/4b6798024f7b2d535f3db1002c760143cdbd1bd3","name":"https://git.kernel.org/stable/c/4b6798024f7b2d535f3db1002c760143cdbd1bd3","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/3c54b66c83fb8fcbde8e6a7bf90b65856e39f827","name":"https://git.kernel.org/stable/c/3c54b66c83fb8fcbde8e6a7bf90b65856e39f827","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/414726b69921fe6355ae453f5b35e68dd078342a","name":"https://git.kernel.org/stable/c/414726b69921fe6355ae453f5b35e68dd078342a","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/8027964931785cb73d520ac70a342a3dc16c249b","name":"https://git.kernel.org/stable/c/8027964931785cb73d520ac70a342a3dc16c249b","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/9ca562bb8e66978b53028fa32b1a190708e6a091","name":"https://git.kernel.org/stable/c/9ca562bb8e66978b53028fa32b1a190708e6a091","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/572ce62778519a7d4d1c15f55dd2e45a474133c4","name":"https://git.kernel.org/stable/c/572ce62778519a7d4d1c15f55dd2e45a474133c4","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-31680","name":"CVE Program record","refsource":"CVE.ORG","tags":["canonical"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-31680","name":"NVD vulnerability detail","refsource":"NVD","tags":["canonical","analysis"]}],"affected":[{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected d3aedd5ebd4b0b925b0bcda548066803e1318499 4b6798024f7b2d535f3db1002c760143cdbd1bd3 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected d3aedd5ebd4b0b925b0bcda548066803e1318499 3c54b66c83fb8fcbde8e6a7bf90b65856e39f827 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected d3aedd5ebd4b0b925b0bcda548066803e1318499 5a6b15f861b7c1304949e3350d23490a5fe429fd git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected d3aedd5ebd4b0b925b0bcda548066803e1318499 6c7fbdb8ffde6413640de7cfbd7c976c353e89f8 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 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semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 5.15.203 5.15.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.1.168 6.1.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.6.134 6.6.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.12.81 6.12.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.18.22 6.18.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.19.12 6.19.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 7.0 * original_commit_for_fix","platforms":[]}],"timeline":[],"solutions":[],"workarounds":[],"exploits":[],"credits":[],"nvd_cpes":[],"vendor_comments":[],"enrichments":{"kev":null,"epss":null,"legacy_qids":[]},"source_records":{"cve_program":{"containers":{"cna":{"affected":[{"defaultStatus":"unaffected","product":"Linux","programFiles":["net/ipv6/ip6_flowlabel.c"],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","vendor":"Linux","versions":[{"lessThan":"4b6798024f7b2d535f3db1002c760143cdbd1bd3","status":"affected","version":"d3aedd5ebd4b0b925b0bcda548066803e1318499","versionType":"git"},{"lessThan":"3c54b66c83fb8fcbde8e6a7bf90b65856e39f827","status":"affected","version":"d3aedd5ebd4b0b925b0bcda548066803e1318499","versionType":"git"},{"lessThan":"5a6b15f861b7c1304949e3350d23490a5fe429fd","status":"affected","version":"d3aedd5ebd4b0b925b0bcda548066803e1318499","versionType":"git"},{"lessThan":"6c7fbdb8ffde6413640de7cfbd7c976c353e89f8","status":"affected","version":"d3aedd5ebd4b0b925b0bcda548066803e1318499","versionType":"git"},{"lessThan":"8027964931785cb73d520ac70a342a3dc16c249b","status":"affected","version":"d3aedd5ebd4b0b925b0bcda548066803e1318499","versionType":"git"},{"lessThan":"414726b69921fe6355ae453f5b35e68dd078342a","status":"affected","version":"d3aedd5ebd4b0b925b0bcda548066803e1318499","versionType":"git"},{"lessThan":"572ce62778519a7d4d1c15f55dd2e45a474133c4","status":"affected","version":"d3aedd5ebd4b0b925b0bcda548066803e1318499","versionType":"git"},{"lessThan":"9ca562bb8e66978b53028fa32b1a190708e6a091","status":"affected","version":"d3aedd5ebd4b0b925b0bcda548066803e1318499","versionType":"git"}]},{"defaultStatus":"affected","product":"Linux","programFiles":["net/ipv6/ip6_flowlabel.c"],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","vendor":"Linux","versions":[{"status":"affected","version":"3.9"},{"lessThan":"3.9","status":"unaffected","version":"0","versionType":"semver"},{"lessThanOrEqual":"5.10.*","status":"unaffected","version":"5.10.253","versionType":"semver"},{"lessThanOrEqual":"5.15.*","status":"unaffected","version":"5.15.203","versionType":"semver"},{"lessThanOrEqual":"6.1.*","status":"unaffected","version":"6.1.168","versionType":"semver"},{"lessThanOrEqual":"6.6.*","status":"unaffected","version":"6.6.134","versionType":"semver"},{"lessThanOrEqual":"6.12.*","status":"unaffected","version":"6.12.81","versionType":"semver"},{"lessThanOrEqual":"6.18.*","status":"unaffected","version":"6.18.22","versionType":"semver"},{"lessThanOrEqual":"6.19.*","status":"unaffected","version":"6.19.12","versionType":"semver"},{"lessThanOrEqual":"*","status":"unaffected","version":"7.0","versionType":"original_commit_for_fix"}]}],"cpeApplicability":[{"nodes":[{"cpeMatch":[{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"5.10.253","versionStartIncluding":"3.9","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"5.15.203","versionStartIncluding":"3.9","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.1.168","versionStartIncluding":"3.9","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.6.134","versionStartIncluding":"3.9","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.12.81","versionStartIncluding":"3.9","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.18.22","versionStartIncluding":"3.9","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.19.12","versionStartIncluding":"3.9","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"7.0","versionStartIncluding":"3.9","vulnerable":true}],"negate":false,"operator":"OR"}]}],"descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nnet: ipv6: flowlabel: defer exclusive option free until RCU teardown\n\n`ip6fl_seq_show()` walks the global flowlabel hash under the seq-file\nRCU read-side lock and prints `fl->opt->opt_nflen` when an option block\nis present.\n\nExclusive flowlabels currently free `fl->opt` as soon as `fl->users`\ndrops to zero in `fl_release()`. However, the surrounding\n`struct ip6_flowlabel` remains visible in the global hash table until\nlater garbage collection removes it and `fl_free_rcu()` finally tears it\ndown.\n\nA concurrent `/proc/net/ip6_flowlabel` reader can therefore race that\nearly `kfree()` and dereference freed option state, triggering a crash\nin `ip6fl_seq_show()`.\n\nFix this by keeping `fl->opt` alive until `fl_free_rcu()`. That matches\nthe lifetime already required for the enclosing flowlabel while readers\ncan still reach it under RCU."}],"providerMetadata":{"dateUpdated":"2026-04-25T08:46:56.807Z","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux"},"references":[{"url":"https://git.kernel.org/stable/c/4b6798024f7b2d535f3db1002c760143cdbd1bd3"},{"url":"https://git.kernel.org/stable/c/3c54b66c83fb8fcbde8e6a7bf90b65856e39f827"},{"url":"https://git.kernel.org/stable/c/5a6b15f861b7c1304949e3350d23490a5fe429fd"},{"url":"https://git.kernel.org/stable/c/6c7fbdb8ffde6413640de7cfbd7c976c353e89f8"},{"url":"https://git.kernel.org/stable/c/8027964931785cb73d520ac70a342a3dc16c249b"},{"url":"https://git.kernel.org/stable/c/414726b69921fe6355ae453f5b35e68dd078342a"},{"url":"https://git.kernel.org/stable/c/572ce62778519a7d4d1c15f55dd2e45a474133c4"},{"url":"https://git.kernel.org/stable/c/9ca562bb8e66978b53028fa32b1a190708e6a091"}],"title":"net: ipv6: flowlabel: defer exclusive option free until RCU teardown","x_generator":{"engine":"bippy-1.2.0"}}},"cveMetadata":{"assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","assignerShortName":"Linux","cveId":"CVE-2026-31680","datePublished":"2026-04-25T08:46:56.807Z","dateReserved":"2026-03-09T15:48:24.130Z","dateUpdated":"2026-04-25T08:46:56.807Z","state":"PUBLISHED"},"dataType":"CVE_RECORD","dataVersion":"5.2"},"nvd":{"publishedDate":"2026-04-25 09:16:01","lastModifiedDate":"2026-04-25 09:16:01","problem_types":[],"metrics":[],"configurations":[]},"legacy_mitre":{"record":{"CveYear":"2026","CveId":"31680","Ordinal":"1","Title":"net: ipv6: flowlabel: defer exclusive option free until RCU tear","CVE":"CVE-2026-31680","Year":"2026"},"notes":[{"CveYear":"2026","CveId":"31680","Ordinal":"1","NoteData":"In the Linux kernel, the following vulnerability has been resolved:\n\nnet: ipv6: flowlabel: defer exclusive option free until RCU teardown\n\n`ip6fl_seq_show()` walks the global flowlabel hash under the seq-file\nRCU read-side lock and prints `fl->opt->opt_nflen` when an option block\nis present.\n\nExclusive flowlabels currently free `fl->opt` as soon as `fl->users`\ndrops to zero in `fl_release()`. However, the surrounding\n`struct ip6_flowlabel` remains visible in the global hash table until\nlater garbage collection removes it and `fl_free_rcu()` finally tears it\ndown.\n\nA concurrent `/proc/net/ip6_flowlabel` reader can therefore race that\nearly `kfree()` and dereference freed option state, triggering a crash\nin `ip6fl_seq_show()`.\n\nFix this by keeping `fl->opt` alive until `fl_free_rcu()`. That matches\nthe lifetime already required for the enclosing flowlabel while readers\ncan still reach it under RCU.","Type":"Description","Title":"net: ipv6: flowlabel: defer exclusive option free until RCU tear"}]}}}