{"dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": {"cveId": "CVE-2026-72423", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-08-09T03:40:39.928Z", "datePublished": "2026-08-15T05:56:41.711Z", "dateUpdated": "2026-08-17T05:44:03.898Z"}, "containers": {"cna": {"providerMetadata": {"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-17T05:44:03.898Z"}, "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nbpf: Guard conntrack opts error writes\n\nThe conntrack lookup and allocation kfuncs take an opts pointer\ntogether with an opts__sz argument. The verifier checks only the memory\nrange described by opts__sz, but the wrappers unconditionally write\nopts->error whenever the internal lookup or allocation helper returns an\nerror.\n\nFor an invalid size smaller than the end of opts->error, that write can\nland outside the verifier-checked range. Keep returning NULL for invalid\narguments, but only report the error through opts->error when the\nsupplied size includes the field.\n\nThis preserves error reporting for the supported 12-byte and 16-byte\nlayouts, and for other invalid sizes that still include opts->error."}], "metrics": [{"cvssV3_1": {"version": "3.1", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H", "baseScore": 8.8, "baseSeverity": "HIGH"}, "scenarios": [{"lang": "en", "value": "AV:L - Exploitation requires loading and attaching a BPF XDP or TC program that calls the conntrack kfuncs via the bpf() syscall; per kernel CNA guidance BPF/netfilter paths are Local even when programs later run on network packets.\nAC:L - An attacker reliably triggers the bug by calling bpf_xdp_ct_lookup/alloc or bpf_skb_ct_lookup/alloc with opts__sz smaller than the error field (e.g. 4); the helper returns EINVAL and the wrapper performs the out-of-bounds write with no races or attacker-uncontrollable conditions.\nPR:L - Loading BPF_PROG_TYPE_XDP or BPF_PROG_TYPE_SCHED_CLS programs requires CAP_NET_ADMIN, which unprivileged users can obtain inside user/network namespaces (unshare -Urn) on typical Linux deployments without init-namespace root.\nUI:N - No victim interaction is required; the attacker loads their own BPF program and invokes the kfunc with a small opts__sz to trigger the out-of-bounds write on demand.\nS:C - Corrupting kernel memory via a verifier-bypassing BPF stack write from a user/network namespace can cross the namespace/container trust boundary to compromise the host kernel, exceeding the attacker's original security scope.\nC:H - The bug is a controlled 4-byte out-of-bounds write past the verifier-approved opts buffer on the BPF stack, a memory-corruption primitive that can be leveraged for arbitrary kernel memory disclosure.\nI:H - Writing opts->error outside the verifier-checked range corrupts adjacent BPF stack slots with attacker-influenced errno values, enabling heap/stack grooming and control-flow hijacking toward arbitrary kernel code execution.\nA:H - Corrupting BPF stack memory outside verifier bounds can cause immediate kernel oops/panic or be used in a repeatable crash/DoS loop when the attached XDP/TC program runs on incoming traffic."}]}], "affected": [{"product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": ["net/netfilter/nf_conntrack_bpf.c"], "versions": [{"version": "b4c2b9593a1c4c3a718370e34af28e817fd5e5c6", "lessThan": "dd74c80203842a21b2ebb9f70d1260d9aa20fa05", "status": "affected", "versionType": "git"}, {"version": "b4c2b9593a1c4c3a718370e34af28e817fd5e5c6", "lessThan": "6f6183a39533d727deaa5061cadae6dd9e6744d0", "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/nf_conntrack_bpf.c"], "versions": [{"version": "5.18", "status": "affected"}, {"version": "0", "lessThan": "5.18", "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": "5.18", "versionEndExcluding": "7.1.5"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.18", "versionEndExcluding": "7.2"}]}]}], "references": [{"url": "https://git.kernel.org/stable/c/dd74c80203842a21b2ebb9f70d1260d9aa20fa05"}, {"url": "https://git.kernel.org/stable/c/6f6183a39533d727deaa5061cadae6dd9e6744d0"}], "title": "bpf: Guard conntrack opts error writes", "x_generator": {"engine": "bippy-1.2.0"}}}}

{}

{"affected": [{"affectedData": [{"defaultStatus": "unaffected", "product": "Linux", "programFiles": ["net/netfilter/nf_conntrack_bpf.c"], "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "vendor": "Linux", "versions": [{"lessThan": "dd74c80203842a21b2ebb9f70d1260d9aa20fa05", "status": "affected", "version": "b4c2b9593a1c4c3a718370e34af28e817fd5e5c6", "versionType": "git"}, {"lessThan": "6f6183a39533d727deaa5061cadae6dd9e6744d0", "status": "affected", "version": "b4c2b9593a1c4c3a718370e34af28e817fd5e5c6", "versionType": "git"}]}, {"defaultStatus": "affected", "product": "Linux", "programFiles": ["net/netfilter/nf_conntrack_bpf.c"], "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "vendor": "Linux", "versions": [{"status": "affected", "version": "5.18"}, {"lessThan": "5.18", "status": "unaffected", "version": "0", "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\nbpf: Guard conntrack opts error writes\n\nThe conntrack lookup and allocation kfuncs take an opts pointer\ntogether with an opts__sz argument. The verifier checks only the memory\nrange described by opts__sz, but the wrappers unconditionally write\nopts->error whenever the internal lookup or allocation helper returns an\nerror.\n\nFor an invalid size smaller than the end of opts->error, that write can\nland outside the verifier-checked range. Keep returning NULL for invalid\narguments, but only report the error through opts->error when the\nsupplied size includes the field.\n\nThis preserves error reporting for the supported 12-byte and 16-byte\nlayouts, and for other invalid sizes that still include opts->error."}], "id": "CVE-2026-72423", "lastModified": "2026-08-17T06:19:09.550", "metrics": {"cvssMetricV31": [{"cvssData": {"attackComplexity": "LOW", "attackVector": "LOCAL", "availabilityImpact": "HIGH", "baseScore": 8.8, "baseSeverity": "HIGH", "confidentialityImpact": "HIGH", "integrityImpact": "HIGH", "privilegesRequired": "LOW", "scope": "CHANGED", "userInteraction": "NONE", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H", "version": "3.1"}, "exploitabilityScore": 2.0, "impactScore": 6.0, "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "type": "Secondary"}]}, "published": "2026-08-15T06:22:16.117", "references": [{"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/6f6183a39533d727deaa5061cadae6dd9e6744d0"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/dd74c80203842a21b2ebb9f70d1260d9aa20fa05"}], "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "vulnStatus": "Received"}

{}