{"api_version":"1","generated_at":"2026-08-22T04:27:12+00:00","cve":"CVE-2026-72254","urls":{"html":"https://cve.report/CVE-2026-72254","api":"https://cve.report/api/cve/CVE-2026-72254.json","docs":"https://cve.report/api","cve_org":"https://www.cve.org/CVERecord?id=CVE-2026-72254","nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-72254"},"summary":{"title":"netfilter: nft_fib: reject fib expression on the netdev egress hook","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nnetfilter: nft_fib: reject fib expression on the netdev egress hook\n\nA fib expression in a netdev egress base chain dereferences nft_in(pkt),\nNULL on the transmit path, causing a NULL pointer dereference at eval.\nnft_fib_validate() masks the hook with NF_INET_* values, but netdev hook\nnumbers are a separate enum that aliases them (NF_NETDEV_EGRESS ==\nNF_INET_LOCAL_IN), so an egress chain passes validation and then faults.\n\nAdd nft_fib_netdev_validate() that limits each result/flag to the netdev\nhook where the device it reads exists: the input-device cases (OIF,\nOIFNAME, ADDRTYPE with F_IIF) to ingress, the output-device case (ADDRTYPE\nwith F_OIF) to egress, ADDRTYPE with no device flag to both. Also restrict\nnft_fib_validate() to NFPROTO_IPV4/IPV6/INET so its NF_INET_* masks are\nnot applied to another family's hooks.","state":"PUBLISHED","assigner":"Linux","published_at":"2026-08-15 06:21:52","updated_at":"2026-08-17 06:18:27"},"problem_types":[],"metrics":[{"version":"3.1","source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","type":"Secondary","score":"7.5","severity":"HIGH","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","data":{"version":"3.1","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","baseScore":7.5,"baseSeverity":"HIGH","attackVector":"NETWORK","attackComplexity":"LOW","privilegesRequired":"NONE","userInteraction":"NONE","scope":"UNCHANGED","confidentialityImpact":"NONE","integrityImpact":"NONE","availabilityImpact":"HIGH"}},{"version":"3.1","source":"CNA","type":"DECLARED","score":"7.5","severity":"HIGH","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","data":{"baseScore":7.5,"baseSeverity":"HIGH","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","version":"3.1"}}],"references":[{"url":"https://git.kernel.org/stable/c/568931f26af4727a51e8521f72efbc78d3b82410","name":"https://git.kernel.org/stable/c/568931f26af4727a51e8521f72efbc78d3b82410","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/f68305267ebda7e839b5e8f77e8d77535a3d5a0f","name":"https://git.kernel.org/stable/c/f68305267ebda7e839b5e8f77e8d77535a3d5a0f","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/d01c913febead04a01a5f3a6374d1f45504dc523","name":"https://git.kernel.org/stable/c/d01c913febead04a01a5f3a6374d1f45504dc523","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/4fee43759b489559a491f7c95f9bfa7a1d0c7a10","name":"https://git.kernel.org/stable/c/4fee43759b489559a491f7c95f9bfa7a1d0c7a10","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/d07955dd34ecae17d35d8c7d0a273a3fba653a8c","name":"https://git.kernel.org/stable/c/d07955dd34ecae17d35d8c7d0a273a3fba653a8c","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-72254","name":"CVE Program record","refsource":"CVE.ORG","tags":["canonical"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-72254","name":"NVD vulnerability detail","refsource":"NVD","tags":["canonical","analysis"]}],"affected":[{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 42df6e1d221dddc0f2acf2be37e68d553ad65f96 4fee43759b489559a491f7c95f9bfa7a1d0c7a10 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 42df6e1d221dddc0f2acf2be37e68d553ad65f96 568931f26af4727a51e8521f72efbc78d3b82410 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 42df6e1d221dddc0f2acf2be37e68d553ad65f96 d01c913febead04a01a5f3a6374d1f45504dc523 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 42df6e1d221dddc0f2acf2be37e68d553ad65f96 f68305267ebda7e839b5e8f77e8d77535a3d5a0f git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 42df6e1d221dddc0f2acf2be37e68d553ad65f96 d07955dd34ecae17d35d8c7d0a273a3fba653a8c 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 6.6.148 6.6.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.12.101 6.12.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.18.42 6.18.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 7.1.5 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":{"cve_year":"2026","cve_id":"72254","cve":"CVE-2026-72254","epss":"0.005950000","percentile":"0.456220000","score_date":"2026-08-17","updated_at":"2026-08-18 00:11:47"},"legacy_qids":[]},"source_records":{"cve_program":{"containers":{"cna":{"affected":[{"defaultStatus":"unaffected","product":"Linux","programFiles":["net/netfilter/nft_fib.c","net/netfilter/nft_fib_netdev.c"],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","vendor":"Linux","versions":[{"lessThan":"4fee43759b489559a491f7c95f9bfa7a1d0c7a10","status":"affected","version":"42df6e1d221dddc0f2acf2be37e68d553ad65f96","versionType":"git"},{"lessThan":"568931f26af4727a51e8521f72efbc78d3b82410","status":"affected","version":"42df6e1d221dddc0f2acf2be37e68d553ad65f96","versionType":"git"},{"lessThan":"d01c913febead04a01a5f3a6374d1f45504dc523","status":"affected","version":"42df6e1d221dddc0f2acf2be37e68d553ad65f96","versionType":"git"},{"lessThan":"f68305267ebda7e839b5e8f77e8d77535a3d5a0f","status":"affected","version":"42df6e1d221dddc0f2acf2be37e68d553ad65f96","versionType":"git"},{"lessThan":"d07955dd34ecae17d35d8c7d0a273a3fba653a8c","status":"affected","version":"42df6e1d221dddc0f2acf2be37e68d553ad65f96","versionType":"git"}]},{"defaultStatus":"affected","product":"Linux","programFiles":["net/netfilter/nft_fib.c","net/netfilter/nft_fib_netdev.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":"6.6.*","status":"unaffected","version":"6.6.148","versionType":"semver"},{"lessThanOrEqual":"6.12.*","status":"unaffected","version":"6.12.101","versionType":"semver"},{"lessThanOrEqual":"6.18.*","status":"unaffected","version":"6.18.42","versionType":"semver"},{"lessThanOrEqual":"7.1.*","status":"unaffected","version":"7.1.5","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":"6.6.148","versionStartIncluding":"5.16","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.12.101","versionStartIncluding":"5.16","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.18.42","versionStartIncluding":"5.16","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"7.1.5","versionStartIncluding":"5.16","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"7.2","versionStartIncluding":"5.16","vulnerable":true}],"negate":false,"operator":"OR"}]}],"descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nnetfilter: nft_fib: reject fib expression on the netdev egress hook\n\nA fib expression in a netdev egress base chain dereferences nft_in(pkt),\nNULL on the transmit path, causing a NULL pointer dereference at eval.\nnft_fib_validate() masks the hook with NF_INET_* values, but netdev hook\nnumbers are a separate enum that aliases them (NF_NETDEV_EGRESS ==\nNF_INET_LOCAL_IN), so an egress chain passes validation and then faults.\n\nAdd nft_fib_netdev_validate() that limits each result/flag to the netdev\nhook where the device it reads exists: the input-device cases (OIF,\nOIFNAME, ADDRTYPE with F_IIF) to ingress, the output-device case (ADDRTYPE\nwith F_OIF) to egress, ADDRTYPE with no device flag to both. Also restrict\nnft_fib_validate() to NFPROTO_IPV4/IPV6/INET so its NF_INET_* masks are\nnot applied to another family's hooks."}],"metrics":[{"cvssV3_1":{"baseScore":7.5,"baseSeverity":"HIGH","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","version":"3.1"},"scenarios":[{"lang":"en","value":"AV:N - Once a netdev egress fib rule is installed, evaluation runs on the packet transmit datapath (nf_hook_egress in __dev_queue_xmit); a remote peer can trigger it by causing the host to send matching IPv4/IPv6 traffic through the hooked interface, matching prior netfilter CNA treatment of pre-deployed nftables rules (e.g. CVE-2026-52998).\nAC:L - No race or uncontrollable victim state is required; with an affected egress fib rule present, the attacker reliably triggers the NULL dereference on the next matching outbound packet by controlling protocol headers and normal connection traffic.\nPR:N - Runtime exploitation needs only network traffic through the netdev egress hook; although installing the fib rule requires CAP_NET_ADMIN, validation incorrectly accepts it as legal, so orchestration or administrators can deploy it and remote attackers need no target credentials or local privileges.\nUI:N - No victim interaction is required beyond ordinary network traffic processing; the kernel automatically evaluates the fib expression on egress without mounts, file opens, or user prompts.\nS:U - Impact is a kernel NULL-pointer fault and host-wide denial of service within the same kernel/network-filtering security authority; it does not constitute VM escape, IOMMU bypass, or another cross-authority boundary change.\nC:N - The failure mode is a NULL pointer dereference of nft_in(pkt) on egress (in is NULL in nf_hook_state_init); there is no use-after-free, out-of-bounds read, or other attacker-controlled memory disclosure primitive.\nI:N - The bug does not corrupt writable memory or provide control-flow hijack; it only dereferences a NULL input device pointer during fib lookup/skipping and cannot modify kernel or user data beyond the immediate fault.\nA:H - The NULL dereference in nft_fib_netdev_eval/nft_fib4_eval/nft_fib6_eval on netdev egress causes a kernel oops/panic-class fault during packet transmission, denying system availability until reboot."}]}],"providerMetadata":{"dateUpdated":"2026-08-17T05:42:07.408Z","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux"},"references":[{"url":"https://git.kernel.org/stable/c/4fee43759b489559a491f7c95f9bfa7a1d0c7a10"},{"url":"https://git.kernel.org/stable/c/568931f26af4727a51e8521f72efbc78d3b82410"},{"url":"https://git.kernel.org/stable/c/d01c913febead04a01a5f3a6374d1f45504dc523"},{"url":"https://git.kernel.org/stable/c/f68305267ebda7e839b5e8f77e8d77535a3d5a0f"},{"url":"https://git.kernel.org/stable/c/d07955dd34ecae17d35d8c7d0a273a3fba653a8c"}],"title":"netfilter: nft_fib: reject fib expression on the netdev egress hook","x_generator":{"engine":"bippy-1.2.0"}}},"cveMetadata":{"assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","assignerShortName":"Linux","cveId":"CVE-2026-72254","datePublished":"2026-08-15T05:54:42.239Z","dateReserved":"2026-08-09T03:40:39.915Z","dateUpdated":"2026-08-17T05:42:07.408Z","state":"PUBLISHED"},"dataType":"CVE_RECORD","dataVersion":"5.2"},"nvd":{"publishedDate":"2026-08-15 06:21:52","lastModifiedDate":"2026-08-17 06:18:27","problem_types":[],"metrics":{"cvssMetricV31":[{"source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","type":"Secondary","cvssData":{"version":"3.1","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","baseScore":7.5,"baseSeverity":"HIGH","attackVector":"NETWORK","attackComplexity":"LOW","privilegesRequired":"NONE","userInteraction":"NONE","scope":"UNCHANGED","confidentialityImpact":"NONE","integrityImpact":"NONE","availabilityImpact":"HIGH"},"exploitabilityScore":3.9,"impactScore":3.6}]},"configurations":[]},"legacy_mitre":{"record":{"CveYear":"2026","CveId":"72254","Ordinal":"1","Title":"netfilter: nft_fib: reject fib expression on the netdev egress h","CVE":"CVE-2026-72254","Year":"2026"},"notes":[{"CveYear":"2026","CveId":"72254","Ordinal":"1","NoteData":"In the Linux kernel, the following vulnerability has been resolved:\n\nnetfilter: nft_fib: reject fib expression on the netdev egress hook\n\nA fib expression in a netdev egress base chain dereferences nft_in(pkt),\nNULL on the transmit path, causing a NULL pointer dereference at eval.\nnft_fib_validate() masks the hook with NF_INET_* values, but netdev hook\nnumbers are a separate enum that aliases them (NF_NETDEV_EGRESS ==\nNF_INET_LOCAL_IN), so an egress chain passes validation and then faults.\n\nAdd nft_fib_netdev_validate() that limits each result/flag to the netdev\nhook where the device it reads exists: the input-device cases (OIF,\nOIFNAME, ADDRTYPE with F_IIF) to ingress, the output-device case (ADDRTYPE\nwith F_OIF) to egress, ADDRTYPE with no device flag to both. Also restrict\nnft_fib_validate() to NFPROTO_IPV4/IPV6/INET so its NF_INET_* masks are\nnot applied to another family's hooks.","Type":"Description","Title":"netfilter: nft_fib: reject fib expression on the netdev egress h"}]}}}