Host hang via unaligned BPF arena teardown
Published Mar 12, 2025 · Updated Aug 5, 2026
Denial of service in BPF arena teardown in affected Linux kernel builds allows local users with CAP_BPF to hang or panic arm64 systems. arena_map_free passes a non-page-aligned address from bpf_arena_get_kern_vm_start to apply_to_existing_page_range, causing apply_to_pte_range to loop without reaching its end address. Exploitation requires an arm64 kernel built with 64 KiB pages and delegated CAP_BPF; the resulting kernel workqueue stall hangs the host, and stray page frees can cause a panic.
Summary
What happened
Denial of service in BPF arena teardown in affected Linux kernel builds allows local users with CAP_BPF to hang or panic arm64 systems. arena_map_free passes a non-page-aligned address from bpf_arena_get_kern_vm_start to apply_to_existing_page_range, causing apply_to_pte_range to loop without reaching its end address. Exploitation requires an arm64 kernel built with 64 KiB pages and delegated CAP_BPF; the resulting kernel workqueue stall hangs the host, and stray page frees can cause a panic.
The record
- CVE
- CVE-2025-21851
- Published
- Mar 12, 2025
- Updated
- Aug 5, 2026
- Vendor
- The Linux Kernel Organization
- Product
- Linux
- Classifications
- T1499
- Attack vector
- local
- Privileges
- authenticated
Timeline
How it unfolded
- Mar 12, 2025CVE publishedPublication date reported by the CVE source.
- Aug 5, 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=317460317a02a1af512697e6e964298dedd8a163 <517e8a7835e8cfb398a0aeb0133de50e31cae32b
- Affected versionversion=317460317a02a1af512697e6e964298dedd8a163 <787d556a3de447e70964a4bdeba9196f62a62b1e
- Affected versionversion=317460317a02a1af512697e6e964298dedd8a163 <c1f3f3892d4526f18aaeffdb6068ce861e793ee3
- Affected versionversion=6.9
What conditions does exploitation require?
What is affected?
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