Incorrect BPF results via missing zero extension
Published Sep 25, 2026 · Updated Sep 25, 2026
Incorrect BPF execution in Linux 6.10 allows local users to retain stale upper register bits after an arena 32-bit cmpxchg. bpf_convert_ctx_accesses rewrites arena atomics as BPF_PROBE_ATOMIC, but is_cmpxchg_insn recognizes only BPF_ATOMIC and skips the required 32-bit result zero extension. Loading the affected arena BPF program requires BPF privileges, and the established consequence is incorrect program behavior rather than a reported kernel compromise.
Summary
What happened
Incorrect BPF execution in Linux 6.10 allows local users to retain stale upper register bits after an arena 32-bit cmpxchg. bpf_convert_ctx_accesses rewrites arena atomics as BPF_PROBE_ATOMIC, but is_cmpxchg_insn recognizes only BPF_ATOMIC and skips the required 32-bit result zero extension. Loading the affected arena BPF program requires BPF privileges, and the established consequence is incorrect program behavior rather than a reported kernel compromise.
The record
- CVE
- CVE-2026-98049
- Published
- Sep 25, 2026
- Updated
- Sep 25, 2026
- Vendor
- The Linux Kernel Organization
- Product
- Linux
- Classifications
- Unavailable
- Attack vector
- local
- Privileges
- admin
Timeline
How it unfolded
- Sep 25, 2026CVE publishedPublication date reported by the CVE source.
- Sep 25, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
Compare your product and version with the public record. A matching version still requires validation against your environment.
Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=6.10
- Affected versionversion=d503a04f8bc0c75dc9db9452d8cc79d748afb752 <1c1b476d43a8b6c9bc04600369dd8cc39950d98e
- Affected versionversion=d503a04f8bc0c75dc9db9452d8cc79d748afb752 <4814ed6406f3493bd554ad046da5f7fc04833571
What conditions does exploitation require?
What is affected?
Published CVSS scores
No CVSS assessment is available in this record.
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.
Activity data is delayed. The latest report is Sep 28, 2026.
Weakness, pattern, technique
No sourced classifications are available.
Public exploit references
No public exploit references are available in this record.
Labels summarize the accepted research assessment. They do not indicate a test against your environment.
Technologies
Your stack
See the directory against your own environment.
Your stack
Check the software in your environment
Get started to see how Hinoki identifies affected software and validates exploitability in your environment.
Get started