{"api_version":"1","generated_at":"2026-08-22T20:04:48+00:00","cve":"CVE-2026-74657","urls":{"html":"https://cve.report/CVE-2026-74657","api":"https://cve.report/api/cve/CVE-2026-74657.json","docs":"https://cve.report/api","cve_org":"https://www.cve.org/CVERecord?id=CVE-2026-74657","nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-74657"},"summary":{"title":"ipv4: Fix fib_nlmsg_size() for RTA_VIA nexthops","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nipv4: Fix fib_nlmsg_size() for RTA_VIA nexthops\n\nfib_nlmsg_size() still estimates nexthop space as if every gateway is\nencoded as an IPv4 RTA_GATEWAY attribute. IPv4 routes can also carry an\nIPv6 gateway, which fib_nexthop_info() dumps as RTA_VIA.\n\nAs a result, route notifications can allocate an skb that is too small.\nfib_dump_info() then fails with -EMSGSIZE and rtmsg_fib() hits the\nWARN_ON() that marks such failures as a fib_nlmsg_size() bug. With\npanic_on_warn set, this becomes a kernel panic.\n\nMirror the actual nexthop dump layout in fib_nlmsg_size(): account for\nIPv6 nexthop gateways dumped as RTA_VIA, for the no-header rtnexthop\nlayout used inside RTA_MULTIPATH, and for RTA_FLOW only when it is\nactually present.","state":"PUBLISHED","assigner":"Linux","published_at":"2026-08-22 16:16:39","updated_at":"2026-08-22 16:16:39"},"problem_types":[],"metrics":[],"references":[{"url":"https://git.kernel.org/stable/c/4ff9548d84945d2cbf9e4c207288063a200ea397","name":"https://git.kernel.org/stable/c/4ff9548d84945d2cbf9e4c207288063a200ea397","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/a59edda6eda1252340354322d8ab318b2e9052fb","name":"https://git.kernel.org/stable/c/a59edda6eda1252340354322d8ab318b2e9052fb","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/4a5dfbae5179f6574695012a980476254df2d295","name":"https://git.kernel.org/stable/c/4a5dfbae5179f6574695012a980476254df2d295","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/7f80ad373ce4a7af5367ff273cea0f16e91387f3","name":"https://git.kernel.org/stable/c/7f80ad373ce4a7af5367ff273cea0f16e91387f3","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/0f0ca602941d0a81ae9514943ca06c55159c6385","name":"https://git.kernel.org/stable/c/0f0ca602941d0a81ae9514943ca06c55159c6385","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/9b22f13524fa0de0d963bbd3002df6c28bae3395","name":"https://git.kernel.org/stable/c/9b22f13524fa0de0d963bbd3002df6c28bae3395","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/5307a53599fa762c06e475ee4a375252074fd324","name":"https://git.kernel.org/stable/c/5307a53599fa762c06e475ee4a375252074fd324","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-74657","name":"CVE Program record","refsource":"CVE.ORG","tags":["canonical"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-74657","name":"NVD vulnerability detail","refsource":"NVD","tags":["canonical","analysis"]}],"affected":[{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected d15662682db232da77136cd348f4c9df312ca6f9 0f0ca602941d0a81ae9514943ca06c55159c6385 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected d15662682db232da77136cd348f4c9df312ca6f9 5307a53599fa762c06e475ee4a375252074fd324 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected d15662682db232da77136cd348f4c9df312ca6f9 7f80ad373ce4a7af5367ff273cea0f16e91387f3 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected d15662682db232da77136cd348f4c9df312ca6f9 4a5dfbae5179f6574695012a980476254df2d295 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected d15662682db232da77136cd348f4c9df312ca6f9 a59edda6eda1252340354322d8ab318b2e9052fb git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected d15662682db232da77136cd348f4c9df312ca6f9 9b22f13524fa0de0d963bbd3002df6c28bae3395 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected d15662682db232da77136cd348f4c9df312ca6f9 4ff9548d84945d2cbf9e4c207288063a200ea397 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 5.2","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 5.2 semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 5.15.216 5.15.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.1.183 6.1.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.6.152 6.6.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.12.104 6.12.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.18.45 6.18.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 7.1.9 7.1.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 7.2 * 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/ipv4/fib_semantics.c"],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","vendor":"Linux","versions":[{"lessThan":"0f0ca602941d0a81ae9514943ca06c55159c6385","status":"affected","version":"d15662682db232da77136cd348f4c9df312ca6f9","versionType":"git"},{"lessThan":"5307a53599fa762c06e475ee4a375252074fd324","status":"affected","version":"d15662682db232da77136cd348f4c9df312ca6f9","versionType":"git"},{"lessThan":"7f80ad373ce4a7af5367ff273cea0f16e91387f3","status":"affected","version":"d15662682db232da77136cd348f4c9df312ca6f9","versionType":"git"},{"lessThan":"4a5dfbae5179f6574695012a980476254df2d295","status":"affected","version":"d15662682db232da77136cd348f4c9df312ca6f9","versionType":"git"},{"lessThan":"a59edda6eda1252340354322d8ab318b2e9052fb","status":"affected","version":"d15662682db232da77136cd348f4c9df312ca6f9","versionType":"git"},{"lessThan":"9b22f13524fa0de0d963bbd3002df6c28bae3395","status":"affected","version":"d15662682db232da77136cd348f4c9df312ca6f9","versionType":"git"},{"lessThan":"4ff9548d84945d2cbf9e4c207288063a200ea397","status":"affected","version":"d15662682db232da77136cd348f4c9df312ca6f9","versionType":"git"}]},{"defaultStatus":"affected","product":"Linux","programFiles":["net/ipv4/fib_semantics.c"],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","vendor":"Linux","versions":[{"status":"affected","version":"5.2"},{"lessThan":"5.2","status":"unaffected","version":"0","versionType":"semver"},{"lessThanOrEqual":"5.15.*","status":"unaffected","version":"5.15.216","versionType":"semver"},{"lessThanOrEqual":"6.1.*","status":"unaffected","version":"6.1.183","versionType":"semver"},{"lessThanOrEqual":"6.6.*","status":"unaffected","version":"6.6.152","versionType":"semver"},{"lessThanOrEqual":"6.12.*","status":"unaffected","version":"6.12.104","versionType":"semver"},{"lessThanOrEqual":"6.18.*","status":"unaffected","version":"6.18.45","versionType":"semver"},{"lessThanOrEqual":"7.1.*","status":"unaffected","version":"7.1.9","versionType":"semver"},{"lessThanOrEqual":"*","status":"unaffected","version":"7.2","versionType":"original_commit_for_fix"}]}],"cpeApplicability":[{"nodes":[{"cpeMatch":[{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"5.15.216","versionStartIncluding":"5.2","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.1.183","versionStartIncluding":"5.2","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.6.152","versionStartIncluding":"5.2","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.12.104","versionStartIncluding":"5.2","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.18.45","versionStartIncluding":"5.2","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"7.1.9","versionStartIncluding":"5.2","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"7.2","versionStartIncluding":"5.2","vulnerable":true}],"negate":false,"operator":"OR"}]}],"descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nipv4: Fix fib_nlmsg_size() for RTA_VIA nexthops\n\nfib_nlmsg_size() still estimates nexthop space as if every gateway is\nencoded as an IPv4 RTA_GATEWAY attribute. IPv4 routes can also carry an\nIPv6 gateway, which fib_nexthop_info() dumps as RTA_VIA.\n\nAs a result, route notifications can allocate an skb that is too small.\nfib_dump_info() then fails with -EMSGSIZE and rtmsg_fib() hits the\nWARN_ON() that marks such failures as a fib_nlmsg_size() bug. With\npanic_on_warn set, this becomes a kernel panic.\n\nMirror the actual nexthop dump layout in fib_nlmsg_size(): account for\nIPv6 nexthop gateways dumped as RTA_VIA, for the no-header rtnexthop\nlayout used inside RTA_MULTIPATH, and for RTA_FLOW only when it is\nactually present."}],"providerMetadata":{"dateUpdated":"2026-08-22T15:32:31.458Z","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux"},"references":[{"url":"https://git.kernel.org/stable/c/0f0ca602941d0a81ae9514943ca06c55159c6385"},{"url":"https://git.kernel.org/stable/c/5307a53599fa762c06e475ee4a375252074fd324"},{"url":"https://git.kernel.org/stable/c/7f80ad373ce4a7af5367ff273cea0f16e91387f3"},{"url":"https://git.kernel.org/stable/c/4a5dfbae5179f6574695012a980476254df2d295"},{"url":"https://git.kernel.org/stable/c/a59edda6eda1252340354322d8ab318b2e9052fb"},{"url":"https://git.kernel.org/stable/c/9b22f13524fa0de0d963bbd3002df6c28bae3395"},{"url":"https://git.kernel.org/stable/c/4ff9548d84945d2cbf9e4c207288063a200ea397"}],"title":"ipv4: Fix fib_nlmsg_size() for RTA_VIA nexthops","x_generator":{"engine":"bippy-1.2.0"}}},"cveMetadata":{"assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","assignerShortName":"Linux","cveId":"CVE-2026-74657","datePublished":"2026-08-22T15:32:31.458Z","dateReserved":"2026-08-15T05:44:03.923Z","dateUpdated":"2026-08-22T15:32:31.458Z","state":"PUBLISHED"},"dataType":"CVE_RECORD","dataVersion":"5.2"},"nvd":{"publishedDate":"2026-08-22 16:16:39","lastModifiedDate":"2026-08-22 16:16:39","problem_types":[],"metrics":[],"configurations":[]},"legacy_mitre":{"record":{"CveYear":"2026","CveId":"74657","Ordinal":"1","Title":"ipv4: Fix fib_nlmsg_size() for RTA_VIA nexthops","CVE":"CVE-2026-74657","Year":"2026"},"notes":[{"CveYear":"2026","CveId":"74657","Ordinal":"1","NoteData":"In the Linux kernel, the following vulnerability has been resolved:\n\nipv4: Fix fib_nlmsg_size() for RTA_VIA nexthops\n\nfib_nlmsg_size() still estimates nexthop space as if every gateway is\nencoded as an IPv4 RTA_GATEWAY attribute. IPv4 routes can also carry an\nIPv6 gateway, which fib_nexthop_info() dumps as RTA_VIA.\n\nAs a result, route notifications can allocate an skb that is too small.\nfib_dump_info() then fails with -EMSGSIZE and rtmsg_fib() hits the\nWARN_ON() that marks such failures as a fib_nlmsg_size() bug. With\npanic_on_warn set, this becomes a kernel panic.\n\nMirror the actual nexthop dump layout in fib_nlmsg_size(): account for\nIPv6 nexthop gateways dumped as RTA_VIA, for the no-header rtnexthop\nlayout used inside RTA_MULTIPATH, and for RTA_FLOW only when it is\nactually present.","Type":"Description","Title":"ipv4: Fix fib_nlmsg_size() for RTA_VIA nexthops"}]}}}