CVE-2026-53671 PUBLISHED

PREVAIL: Context-write no-op in do_mem_store allows unsafe eBPF programs to pass verification

Assigner: GitHub_M
Reserved: 09.06.2026 Published: 02.09.2026 Updated: 02.09.2026

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.

Metrics

CVSS 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
CVSS Score: 9.3

Product Status

Vendor vbpf
Product prevail
Versions
  • Version < 0.2.4 is affected

References

Problem Types

  • CWE-682: Incorrect Calculation CWE