{"dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": {"cveId": "CVE-2026-72254", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-08-09T03:40:39.915Z", "datePublished": "2026-08-15T05:54:42.239Z", "dateUpdated": "2026-08-17T05:42:07.408Z"}, "containers": {"cna": {"providerMetadata": {"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-17T05:42:07.408Z"}, "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": {"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"}, "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."}]}], "affected": [{"product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": ["net/netfilter/nft_fib.c", "net/netfilter/nft_fib_netdev.c"], "versions": [{"version": "42df6e1d221dddc0f2acf2be37e68d553ad65f96", "lessThan": "4fee43759b489559a491f7c95f9bfa7a1d0c7a10", "status": "affected", "versionType": "git"}, {"version": "42df6e1d221dddc0f2acf2be37e68d553ad65f96", "lessThan": "568931f26af4727a51e8521f72efbc78d3b82410", "status": "affected", "versionType": "git"}, {"version": "42df6e1d221dddc0f2acf2be37e68d553ad65f96", "lessThan": "d01c913febead04a01a5f3a6374d1f45504dc523", "status": "affected", "versionType": "git"}, {"version": "42df6e1d221dddc0f2acf2be37e68d553ad65f96", "lessThan": "f68305267ebda7e839b5e8f77e8d77535a3d5a0f", "status": "affected", "versionType": "git"}, {"version": "42df6e1d221dddc0f2acf2be37e68d553ad65f96", "lessThan": "d07955dd34ecae17d35d8c7d0a273a3fba653a8c", "status": "affected", "versionType": "git"}]}, {"product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": ["net/netfilter/nft_fib.c", "net/netfilter/nft_fib_netdev.c"], "versions": [{"version": "5.16", "status": "affected"}, {"version": "0", "lessThan": "5.16", "status": "unaffected", "versionType": "semver"}, {"version": "6.6.148", "lessThanOrEqual": "6.6.*", "status": "unaffected", "versionType": "semver"}, {"version": "6.12.101", "lessThanOrEqual": "6.12.*", "status": "unaffected", "versionType": "semver"}, {"version": "6.18.42", "lessThanOrEqual": "6.18.*", "status": "unaffected", "versionType": "semver"}, {"version": "7.1.5", "lessThanOrEqual": "7.1.*", "status": "unaffected", "versionType": "semver"}, {"version": "7.2", "lessThanOrEqual": "*", "status": "unaffected", "versionType": "original_commit_for_fix"}]}], "cpeApplicability": [{"nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.16", "versionEndExcluding": "6.6.148"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.16", "versionEndExcluding": "6.12.101"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.16", "versionEndExcluding": "6.18.42"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.16", "versionEndExcluding": "7.1.5"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.16", "versionEndExcluding": "7.2"}]}]}], "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"}}}}

{}

{"affected": [{"affectedData": [{"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"}]}], "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}], "cveTags": [], "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."}], "id": "CVE-2026-72254", "lastModified": "2026-08-17T06:18:27.610", "metrics": {"cvssMetricV31": [{"cvssData": {"attackComplexity": "LOW", "attackVector": "NETWORK", "availabilityImpact": "HIGH", "baseScore": 7.5, "baseSeverity": "HIGH", "confidentialityImpact": "NONE", "integrityImpact": "NONE", "privilegesRequired": "NONE", "scope": "UNCHANGED", "userInteraction": "NONE", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H", "version": "3.1"}, "exploitabilityScore": 3.9, "impactScore": 3.6, "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "type": "Secondary"}]}, "published": "2026-08-15T06:21:52.910", "references": [{"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/4fee43759b489559a491f7c95f9bfa7a1d0c7a10"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/568931f26af4727a51e8521f72efbc78d3b82410"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/d01c913febead04a01a5f3a6374d1f45504dc523"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/d07955dd34ecae17d35d8c7d0a273a3fba653a8c"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/f68305267ebda7e839b5e8f77e8d77535a3d5a0f"}], "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "vulnStatus": "Received"}

{"bugzilla": {"description": "kernel: netfilter: nft_fib: reject fib expression on the netdev egress hook", "id": "2516308", "url": "https://bugzilla.redhat.com/show_bug.cgi?id=2516308"}, "csaw": false, "cvss3": {"cvss3_base_score": "5.5", "cvss3_scoring_vector": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H", "status": "draft"}, "cwe": "CWE-476", "details": ["A flaw was found in the Linux kernel's `netfilter` subsystem. A local attacker could exploit a vulnerability where a `fib` expression in a `netdev egress base chain` incorrectly dereferences a NULL pointer. This can lead to a NULL pointer dereference, causing a system crash and resulting in a Denial of Service (DoS)."], "name": "CVE-2026-72254", "package_state": [{"cpe": "cpe:/o:redhat:enterprise_linux:10", "fix_state": "Fix deferred", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 10"}, {"cpe": "cpe:/o:redhat:enterprise_linux:6", "fix_state": "Not affected", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 6"}, {"cpe": "cpe:/o:redhat:enterprise_linux:7", "fix_state": "Not affected", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 7"}, {"cpe": "cpe:/o:redhat:enterprise_linux:7", "fix_state": "Not affected", "package_name": "kernel-rt", "product_name": "Red Hat Enterprise Linux 7"}, {"cpe": "cpe:/o:redhat:enterprise_linux:8", "fix_state": "Not affected", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 8"}, {"cpe": "cpe:/o:redhat:enterprise_linux:8", "fix_state": "Not affected", "package_name": "kernel-rt", "product_name": "Red Hat Enterprise Linux 8"}, {"cpe": "cpe:/o:redhat:enterprise_linux:9", "fix_state": "Fix deferred", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 9"}, {"cpe": "cpe:/o:redhat:enterprise_linux:9", "fix_state": "Fix deferred", "package_name": "kernel-rt", "product_name": "Red Hat Enterprise Linux 9"}], "public_date": "2026-08-15T00:00:00Z", "references": ["https://www.cve.org/CVERecord?id=CVE-2026-72254\nhttps://nvd.nist.gov/vuln/detail/CVE-2026-72254\nhttps://lore.kernel.org/linux-cve-announce/2026081553-CVE-2026-72254-fb72@gregkh/T"], "threat_severity": "Low"}