CVE-2025-21851
7.8 · HIGHOverview
CVE-2025-21851 is a high-severity vulnerability affecting linux linux_kernel. It was published on March 12, 2025 and has a CVSS 3.1 base score of 7.8 (HIGH).
This vulnerability has a CVSS 3.1 base score of 7.8, rated HIGH. It requires local or adjacent network access to exploit. Some level of privileges is required for exploitation.
Technical Description
In the Linux kernel, the following vulnerability has been resolved:
bpf: Fix softlockup in arena_map_free on 64k page kernel
On an aarch64 kernel with CONFIG_PAGE_SIZE_64KB=y,
arena_htab tests cause a segmentation fault and soft lockup.
The same failure is not observed with 4k pages on aarch64.
It turns out arena_map_free() is calling
apply_to_existing_page_range() with the address returned by
bpf_arena_get_kern_vm_start(). If this address is not page-aligned
the code ends up calling apply_to_pte_range() with that unaligned
address causing soft lockup.
Fix it by round up GUARD_SZ to PAGE_SIZE << 1 so that the
division by 2 in bpf_arena_get_kern_vm_start() returns
a page-aligned value.
Remediation
Check the references section for vendor advisories and patches from linux. Update linux_kernel to the latest patched version. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.
Affected Products
| Vendor | Product | Versions | Status |
|---|---|---|---|
| linux | linux_kernel | >= 6.9, < 6.12.17 | Affected |
Frequently Asked Questions
What is CVE-2025-21851?
CVE-2025-21851 is a high-severity vulnerability affecting linux linux_kernel. It was published on March 12, 2025 and has a CVSS 3.1 base score of 7.8 (HIGH).
How severe is CVE-2025-21851?
This vulnerability has a CVSS 3.1 base score of 7.8, rated HIGH. It requires local or adjacent network access to exploit. Some level of privileges is required for exploitation.
How do I fix or remediate CVE-2025-21851?
Check the references section for vendor advisories and patches from linux. Update linux_kernel to the latest patched version. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.
How can CyberStrike help with CVE-2025-21851?
CyberStrike's AI-powered security agents can automatically detect CVE-2025-21851 across your infrastructure using autonomous pentesting, DAST scanning, and HackBrowser. The platform continuously monitors for known vulnerabilities and provides actionable remediation guidance prioritized by real-world exploitability.
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