Unsafe eBPF acceptance via ignored context writes
Published Sep 2, 2026 · Updated Sep 2, 2026
Incorrect calculation in PREVAIL before 0.2.4 allows attackers to pass unsafe eBPF programs via crafted object files. The do_mem_store transformer ignores writes through T_CTX-typed base registers, while check_valid_access bounds context accesses without rejecting writes, so later loads reuse stale abstract state. The security consequence is confined to deployments where a kernel or runtime trusts that verdict before loading the program, exposing memory to corruption or disclosure.
Summary
What happened
Incorrect calculation in PREVAIL before 0.2.4 allows attackers to pass unsafe eBPF programs via crafted object files. The do_mem_store transformer ignores writes through T_CTX-typed base registers, while check_valid_access bounds context accesses without rejecting writes, so later loads reuse stale abstract state. The security consequence is confined to deployments where a kernel or runtime trusts that verdict before loading the program, exposing memory to corruption or disclosure.
The record
- CVE
- CVE-2026-53671
- Published
- Sep 2, 2026
- Updated
- Sep 2, 2026
- Vendor
- vbpf
- Product
- PREVAIL
- Classifications
- CWE-682
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Sep 2, 2026CVE publishedPublication date reported by the CVE source.
- Sep 2, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=< 0.2.4
What conditions does exploitation require?
What is affected?
Published CVSS scores
CVSS describes severity. EPSS estimates exploitation probability.
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Weakness, pattern, technique
Public exploit references
- GHSA context-write reproduction procedureproof of concept · demonstrated
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Technologies
Your stack
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Your stack
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