{"id":"CVE-2026-53671","state":"PUBLISHED","title":"PREVAIL: Context-write no-op in do_mem_store allows unsafe eBPF programs to pass verification","description":"PREVAIL is a Polynomial-Runtime EBPF Verifier using an Abstract Interpretation Layer. Prior to version 0.2.4, the abstract transformer in prevail treats writes through a T_CTX-typed base register as a silent no-op: do_mem_store in src/crab/ebpf_transformer.cpp only models T_STACK stores, and the checker's T_CTX bounds arm never tests AccessType::write. An attacker can craft an eBPF program that overwrites a context field (e.g., ctx->data), reload that field typed as T_PACKET, and dereference an attacker-controlled address — and prevail will report the program as safe. This issue has been patched in version 0.2.4.","publishedAt":"2026-09-02T17:54:30.682Z","updatedAt":"2026-09-05T01:00:30.688Z","severity":{"score":9.3,"label":"Critical","version":"4.0","vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N","source":"GitHub_M"},"assigner":"GitHub_M","products":["vbpf prevail"],"affected":[{"vendor":"vbpf","product":"prevail","versions":[{"version":"< 0.2.4","status":"affected"}]}],"references":["https://github.com/vbpf/prevail/security/advisories/GHSA-65rv-h458-cq99","https://github.com/vbpf/prevail/commit/de65234f67d2608b54d12571edb585ead224363c","https://github.com/vbpf/prevail/releases/tag/v0.2.4"],"weaknesses":["CWE-682"],"ingestedAt":"2026-10-29T20:12:16.098Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/53xxx/CVE-2026-53671.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-53671","state":"PUBLISHED","datePublished":"2026-09-02T17:54:30.682Z","dateUpdated":"2026-09-05T01:00:30.688Z","assignerShortName":"GitHub_M","assignerOrgId":"a0819718-46f1-4df5-94e2-005712e83aaa","dateReserved":"2026-06-09T20:50:36.878Z"},"containers":{"cna":{"title":"PREVAIL: Context-write no-op in do_mem_store allows unsafe eBPF programs to pass verification","descriptions":[{"lang":"en","value":"PREVAIL is a Polynomial-Runtime EBPF Verifier using an Abstract Interpretation Layer. Prior to version 0.2.4, the abstract transformer in prevail treats writes through a T_CTX-typed base register as a silent no-op: do_mem_store in src/crab/ebpf_transformer.cpp only models T_STACK stores, and the checker's T_CTX bounds arm never tests AccessType::write. An attacker can craft an eBPF program that overwrites a context field (e.g., ctx->data), reload that field typed as T_PACKET, and dereference an attacker-controlled address — and prevail will report the program as safe. This issue has been patched in version 0.2.4."}],"affected":[{"vendor":"vbpf","product":"prevail","versions":[{"version":"< 0.2.4","status":"affected"}]}],"references":[{"url":"https://github.com/vbpf/prevail/security/advisories/GHSA-65rv-h458-cq99","name":"https://github.com/vbpf/prevail/security/advisories/GHSA-65rv-h458-cq99","tags":["x_refsource_CONFIRM"]},{"url":"https://github.com/vbpf/prevail/commit/de65234f67d2608b54d12571edb585ead224363c","name":"https://github.com/vbpf/prevail/commit/de65234f67d2608b54d12571edb585ead224363c","tags":["x_refsource_MISC"]},{"url":"https://github.com/vbpf/prevail/releases/tag/v0.2.4","name":"https://github.com/vbpf/prevail/releases/tag/v0.2.4","tags":["x_refsource_MISC"]}],"metrics":[{"cvssV4_0":{"attackVector":"NETWORK","attackComplexity":"LOW","attackRequirements":"NONE","privilegesRequired":"NONE","userInteraction":"NONE","vulnConfidentialityImpact":"HIGH","vulnIntegrityImpact":"HIGH","vulnAvailabilityImpact":"NONE","subConfidentialityImpact":"NONE","subIntegrityImpact":"NONE","subAvailabilityImpact":"NONE","baseScore":9.3,"baseSeverity":"CRITICAL","vectorString":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N","version":"4.0"}}],"problemTypes":[{"descriptions":[{"cweId":"CWE-682","lang":"en","description":"CWE-682: Incorrect Calculation","type":"CWE"}]}],"providerMetadata":{"shortName":"GitHub_M","orgId":"a0819718-46f1-4df5-94e2-005712e83aaa","dateUpdated":"2026-09-02T17:54:30.682Z"},"source":{"advisory":"GHSA-65rv-h458-cq99","discovery":"UNKNOWN"}},"adp":[{"title":"CISA ADP Vulnrichment","references":[{"url":"https://github.com/vbpf/prevail/security/advisories/GHSA-65rv-h458-cq99","tags":["exploit"]}],"metrics":[{"other":{"type":"ssvc","content":{"timestamp":"2026-09-05T00:59:35.326258Z","id":"CVE-2026-53671","options":[{"Exploitation":"poc"},{"Automatable":"yes"},{"Technical Impact":"total"}],"role":"CISA Coordinator","version":"2.0.3"}}}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2026-09-05T01:00:30.688Z"}}]}}}