CVE-2026-53671 PREVAIL: Context-write no-op in do_mem_store allows unsafe eBPF programs to pass verification
A flaw in the PREVAIL eBPF verifier allows unsafe programs to bypass checks, potentially enabling arbitrary code execution or privilege escalation.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2026-53671?
CVE-2026-53671 is a critical vulnerability in vbpf prevail, published on 2 Sep 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official 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.
Weakness: CWE-682
Which versions are affected by CVE-2026-53671?
How do I fix CVE-2026-53671?
No fix has been published for CVE-2026-53671 yet. Limit exposure of the affected software until one is available.
Is CVE-2026-53671 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-53671 exists.
Sources
Also known as GHSA-65rv-h458-cq99.