Kernel crash via misextended BPF pointer return
Published Oct 28, 2025 · Updated Oct 28, 2025
Incorrect return-value handling in the RISC-V BPF JIT in Linux allows local users to crash the kernel through a struct_ops program. The JIT epilogue treats bpf_fifo_dequeue's skb pointer as a 32-bit value and sign-extends it to 64 bits instead of following the struct_ops function model and RISC-V ABI. Reachability requires a RISC-V host and the ability to load the affected BPF struct_ops program; the demonstrated result is an invalid kernel pointer dereference and panic.
Summary
What happened
Incorrect return-value handling in the RISC-V BPF JIT in Linux allows local users to crash the kernel through a struct_ops program. The JIT epilogue treats bpf_fifo_dequeue's skb pointer as a 32-bit value and sign-extends it to 64 bits instead of following the struct_ops function model and RISC-V ABI. Reachability requires a RISC-V host and the ability to load the affected BPF struct_ops program; the demonstrated result is an invalid kernel pointer dereference and panic.
The record
- CVE
- CVE-2025-40079
- Published
- Oct 28, 2025
- Updated
- Oct 28, 2025
- Vendor
- The Linux Kernel Organization
- Product
- Linux
- Classifications
- T1499.004
- Attack vector
- local
- Privileges
- authenticated
Timeline
How it unfolded
- Oct 28, 2025CVE publishedPublication date reported by the CVE source.
- Oct 28, 2025Record 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=25ad10658dc1068a671553ff10e19a812c2a3783 <918a399501e28e0cc36dbd1fcfb4208f8aa1e4d1
- Affected versionversion=25ad10658dc1068a671553ff10e19a812c2a3783 <92751937f12a7d34ad492577a251c94a55e97e72
- Affected versionversion=25ad10658dc1068a671553ff10e19a812c2a3783 <fd2e08128944a7679e753f920e9eda72057e427c
- Affected versionversion=6.6
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
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
Book a demo to see how Hinoki identifies affected software and validates exploitability in your environment.
Book a demo