{"api_version":"1","generated_at":"2026-05-12T00:55:11+00:00","cve":"CVE-2026-43455","urls":{"html":"https://cve.report/CVE-2026-43455","api":"https://cve.report/api/cve/CVE-2026-43455.json","docs":"https://cve.report/api","cve_org":"https://www.cve.org/CVERecord?id=CVE-2026-43455","nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-43455"},"summary":{"title":"mctp: route: hold key->lock in mctp_flow_prepare_output()","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nmctp: route: hold key->lock in mctp_flow_prepare_output()\n\nmctp_flow_prepare_output() checks key->dev and may call\nmctp_dev_set_key(), but it does not hold key->lock while doing so.\n\nmctp_dev_set_key() and mctp_dev_release_key() are annotated with\n__must_hold(&key->lock), so key->dev access is intended to be\nserialized by key->lock. The mctp_sendmsg() transmit path reaches\nmctp_flow_prepare_output() via mctp_local_output() -> mctp_dst_output()\nwithout holding key->lock, so the check-and-set sequence is racy.\n\nExample interleaving:\n\n  CPU0                                  CPU1\n  ----                                  ----\n  mctp_flow_prepare_output(key, devA)\n    if (!key->dev)  // sees NULL\n                                        mctp_flow_prepare_output(\n                                            key, devB)\n                                          if (!key->dev)  // still NULL\n                                          mctp_dev_set_key(devB, key)\n                                            mctp_dev_hold(devB)\n                                            key->dev = devB\n    mctp_dev_set_key(devA, key)\n      mctp_dev_hold(devA)\n      key->dev = devA   // overwrites devB\n\nNow both devA and devB references were acquired, but only the final\nkey->dev value is tracked for release. One reference can be lost,\ncausing a resource leak as mctp_dev_release_key() would only decrease\nthe reference on one dev.\n\nFix by taking key->lock around the key->dev check and\nmctp_dev_set_key() call.","state":"PUBLISHED","assigner":"Linux","published_at":"2026-05-08 15:16:58","updated_at":"2026-05-08 15:16:58"},"problem_types":[],"metrics":[],"references":[{"url":"https://git.kernel.org/stable/c/0695712f3a6f1a48915f95767cfb42077683dcdc","name":"https://git.kernel.org/stable/c/0695712f3a6f1a48915f95767cfb42077683dcdc","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/47893166bc5611ee9a20de6b8d2933b2320fb772","name":"https://git.kernel.org/stable/c/47893166bc5611ee9a20de6b8d2933b2320fb772","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/86f5334fcb48a5b611c33364ab52ca684d0f6d91","name":"https://git.kernel.org/stable/c/86f5334fcb48a5b611c33364ab52ca684d0f6d91","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/925a5ffd99cddd7a7e41d5ad120c7a2c6d50260f","name":"https://git.kernel.org/stable/c/925a5ffd99cddd7a7e41d5ad120c7a2c6d50260f","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/7d86aa41c073c4e7eb75fd2e674f1fd8f289728a","name":"https://git.kernel.org/stable/c/7d86aa41c073c4e7eb75fd2e674f1fd8f289728a","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/8d27d9b260dd19c1b519e1a13de6448f9984e30e","name":"https://git.kernel.org/stable/c/8d27d9b260dd19c1b519e1a13de6448f9984e30e","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-43455","name":"CVE Program record","refsource":"CVE.ORG","tags":["canonical"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-43455","name":"NVD vulnerability detail","refsource":"NVD","tags":["canonical","analysis"]}],"affected":[{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 67737c457281dd199ceb9e31b6ba7efd3bfe566d 47893166bc5611ee9a20de6b8d2933b2320fb772 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 67737c457281dd199ceb9e31b6ba7efd3bfe566d 86f5334fcb48a5b611c33364ab52ca684d0f6d91 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 67737c457281dd199ceb9e31b6ba7efd3bfe566d 0695712f3a6f1a48915f95767cfb42077683dcdc git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 67737c457281dd199ceb9e31b6ba7efd3bfe566d 925a5ffd99cddd7a7e41d5ad120c7a2c6d50260f git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 67737c457281dd199ceb9e31b6ba7efd3bfe566d 8d27d9b260dd19c1b519e1a13de6448f9984e30e git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 67737c457281dd199ceb9e31b6ba7efd3bfe566d 7d86aa41c073c4e7eb75fd2e674f1fd8f289728a git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 5.16","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 5.16 semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.1.167 6.1.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.6.130 6.6.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.12.78 6.12.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.18.19 6.18.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.19.9 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":{"cve_year":"2026","cve_id":"43455","cve":"CVE-2026-43455","epss":"0.000240000","percentile":"0.070210000","score_date":"2026-05-11","updated_at":"2026-05-12 00:01:17"},"legacy_qids":[]},"source_records":{"cve_program":{"containers":{"cna":{"affected":[{"defaultStatus":"unaffected","product":"Linux","programFiles":["net/mctp/route.c"],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","vendor":"Linux","versions":[{"lessThan":"47893166bc5611ee9a20de6b8d2933b2320fb772","status":"affected","version":"67737c457281dd199ceb9e31b6ba7efd3bfe566d","versionType":"git"},{"lessThan":"86f5334fcb48a5b611c33364ab52ca684d0f6d91","status":"affected","version":"67737c457281dd199ceb9e31b6ba7efd3bfe566d","versionType":"git"},{"lessThan":"0695712f3a6f1a48915f95767cfb42077683dcdc","status":"affected","version":"67737c457281dd199ceb9e31b6ba7efd3bfe566d","versionType":"git"},{"lessThan":"925a5ffd99cddd7a7e41d5ad120c7a2c6d50260f","status":"affected","version":"67737c457281dd199ceb9e31b6ba7efd3bfe566d","versionType":"git"},{"lessThan":"8d27d9b260dd19c1b519e1a13de6448f9984e30e","status":"affected","version":"67737c457281dd199ceb9e31b6ba7efd3bfe566d","versionType":"git"},{"lessThan":"7d86aa41c073c4e7eb75fd2e674f1fd8f289728a","status":"affected","version":"67737c457281dd199ceb9e31b6ba7efd3bfe566d","versionType":"git"}]},{"defaultStatus":"affected","product":"Linux","programFiles":["net/mctp/route.c"],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","vendor":"Linux","versions":[{"status":"affected","version":"5.16"},{"lessThan":"5.16","status":"unaffected","version":"0","versionType":"semver"},{"lessThanOrEqual":"6.1.*","status":"unaffected","version":"6.1.167","versionType":"semver"},{"lessThanOrEqual":"6.6.*","status":"unaffected","version":"6.6.130","versionType":"semver"},{"lessThanOrEqual":"6.12.*","status":"unaffected","version":"6.12.78","versionType":"semver"},{"lessThanOrEqual":"6.18.*","status":"unaffected","version":"6.18.19","versionType":"semver"},{"lessThanOrEqual":"6.19.*","status":"unaffected","version":"6.19.9","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":"6.1.167","versionStartIncluding":"5.16","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.6.130","versionStartIncluding":"5.16","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.12.78","versionStartIncluding":"5.16","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.18.19","versionStartIncluding":"5.16","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.19.9","versionStartIncluding":"5.16","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"7.0","versionStartIncluding":"5.16","vulnerable":true}],"negate":false,"operator":"OR"}]}],"descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nmctp: route: hold key->lock in mctp_flow_prepare_output()\n\nmctp_flow_prepare_output() checks key->dev and may call\nmctp_dev_set_key(), but it does not hold key->lock while doing so.\n\nmctp_dev_set_key() and mctp_dev_release_key() are annotated with\n__must_hold(&key->lock), so key->dev access is intended to be\nserialized by key->lock. The mctp_sendmsg() transmit path reaches\nmctp_flow_prepare_output() via mctp_local_output() -> mctp_dst_output()\nwithout holding key->lock, so the check-and-set sequence is racy.\n\nExample interleaving:\n\n  CPU0                                  CPU1\n  ----                                  ----\n  mctp_flow_prepare_output(key, devA)\n    if (!key->dev)  // sees NULL\n                                        mctp_flow_prepare_output(\n                                            key, devB)\n                                          if (!key->dev)  // still NULL\n                                          mctp_dev_set_key(devB, key)\n                                            mctp_dev_hold(devB)\n                                            key->dev = devB\n    mctp_dev_set_key(devA, key)\n      mctp_dev_hold(devA)\n      key->dev = devA   // overwrites devB\n\nNow both devA and devB references were acquired, but only the final\nkey->dev value is tracked for release. One reference can be lost,\ncausing a resource leak as mctp_dev_release_key() would only decrease\nthe reference on one dev.\n\nFix by taking key->lock around the key->dev check and\nmctp_dev_set_key() call."}],"providerMetadata":{"dateUpdated":"2026-05-08T14:22:19.375Z","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux"},"references":[{"url":"https://git.kernel.org/stable/c/47893166bc5611ee9a20de6b8d2933b2320fb772"},{"url":"https://git.kernel.org/stable/c/86f5334fcb48a5b611c33364ab52ca684d0f6d91"},{"url":"https://git.kernel.org/stable/c/0695712f3a6f1a48915f95767cfb42077683dcdc"},{"url":"https://git.kernel.org/stable/c/925a5ffd99cddd7a7e41d5ad120c7a2c6d50260f"},{"url":"https://git.kernel.org/stable/c/8d27d9b260dd19c1b519e1a13de6448f9984e30e"},{"url":"https://git.kernel.org/stable/c/7d86aa41c073c4e7eb75fd2e674f1fd8f289728a"}],"title":"mctp: route: hold key->lock in mctp_flow_prepare_output()","x_generator":{"engine":"bippy-1.2.0"}}},"cveMetadata":{"assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","assignerShortName":"Linux","cveId":"CVE-2026-43455","datePublished":"2026-05-08T14:22:19.375Z","dateReserved":"2026-05-01T14:12:56.010Z","dateUpdated":"2026-05-08T14:22:19.375Z","state":"PUBLISHED"},"dataType":"CVE_RECORD","dataVersion":"5.2"},"nvd":{"publishedDate":"2026-05-08 15:16:58","lastModifiedDate":"2026-05-08 15:16:58","problem_types":[],"metrics":[],"configurations":[]},"legacy_mitre":{"record":{"CveYear":"2026","CveId":"43455","Ordinal":"1","Title":"mctp: route: hold key->lock in mctp_flow_prepare_output()","CVE":"CVE-2026-43455","Year":"2026"},"notes":[{"CveYear":"2026","CveId":"43455","Ordinal":"1","NoteData":"In the Linux kernel, the following vulnerability has been resolved:\n\nmctp: route: hold key->lock in mctp_flow_prepare_output()\n\nmctp_flow_prepare_output() checks key->dev and may call\nmctp_dev_set_key(), but it does not hold key->lock while doing so.\n\nmctp_dev_set_key() and mctp_dev_release_key() are annotated with\n__must_hold(&key->lock), so key->dev access is intended to be\nserialized by key->lock. The mctp_sendmsg() transmit path reaches\nmctp_flow_prepare_output() via mctp_local_output() -> mctp_dst_output()\nwithout holding key->lock, so the check-and-set sequence is racy.\n\nExample interleaving:\n\n  CPU0                                  CPU1\n  ----                                  ----\n  mctp_flow_prepare_output(key, devA)\n    if (!key->dev)  // sees NULL\n                                        mctp_flow_prepare_output(\n                                            key, devB)\n                                          if (!key->dev)  // still NULL\n                                          mctp_dev_set_key(devB, key)\n                                            mctp_dev_hold(devB)\n                                            key->dev = devB\n    mctp_dev_set_key(devA, key)\n      mctp_dev_hold(devA)\n      key->dev = devA   // overwrites devB\n\nNow both devA and devB references were acquired, but only the final\nkey->dev value is tracked for release. One reference can be lost,\ncausing a resource leak as mctp_dev_release_key() would only decrease\nthe reference on one dev.\n\nFix by taking key->lock around the key->dev check and\nmctp_dev_set_key() call.","Type":"Description","Title":"mctp: route: hold key->lock in mctp_flow_prepare_output()"}]}}}