{"id":"CVE-2026-53671","aliases":["GHSA-65rv-h458-cq99"],"url":"https://o3.security/vulnerability/CVE-2026-53671","summary":"PREVAIL: Context-write no-op in do_mem_store allows unsafe eBPF programs to pass verification","details":"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.","published":"2026-09-02T17:54:30.682Z","modified":"2026-09-04T08:05:25.998866Z","cvss":null,"epss":null,"cisaKev":null,"exploitsKnown":null,"affectedPackages":[],"fix":{"url":"https://github.com/vbpf/prevail/commit/de65234f67d2608b54d12571edb585ead224363c","label":"vbpf/prevail@de65234"},"references":[{"type":"WEB","url":"https://github.com/vbpf/prevail/releases/tag/v0.2.4"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/53xxx/CVE-2026-53671.json"},{"type":"ADVISORY","url":"https://github.com/vbpf/prevail/security/advisories/GHSA-65rv-h458-cq99"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-53671"},{"type":"FIX","url":"https://github.com/vbpf/prevail/commit/de65234f67d2608b54d12571edb585ead224363c"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-09-04T08:05:25.998866Z"}}