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CVE-2025-21853

5.5 · MEDIUM
Published Mar 12, 2025 linux EPSS 0.24% (15th pctl)

Overview

CVE-2025-21853 is a medium-severity vulnerability affecting linux linux_kernel. It was published on March 12, 2025 and has a CVSS 3.1 base score of 5.5 (MEDIUM).

This vulnerability has a CVSS 3.1 base score of 5.5, rated MEDIUM. 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: avoid holding freeze_mutex during mmap operation

We use map->freeze_mutex to prevent races between map_freeze() and

memory mapping BPF map contents with writable permissions. The way we

naively do this means we'll hold freeze_mutex for entire duration of all

the mm and VMA manipulations, which is completely unnecessary. This can

potentially also lead to deadlocks, as reported by syzbot in [0].

So, instead, hold freeze_mutex only during writeability checks, bump

(proactively) "write active" count for the map, unlock the mutex and

proceed with mmap logic. And only if something went wrong during mmap

logic, then undo that "write active" counter increment.

[0] https://lore.kernel.org/bpf/[email protected]/

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 >= 5.5, < 6.6.80 Affected

Frequently Asked Questions

What is CVE-2025-21853?

CVE-2025-21853 is a medium-severity vulnerability affecting linux linux_kernel. It was published on March 12, 2025 and has a CVSS 3.1 base score of 5.5 (MEDIUM).

How severe is CVE-2025-21853?

This vulnerability has a CVSS 3.1 base score of 5.5, rated MEDIUM. It requires local or adjacent network access to exploit. Some level of privileges is required for exploitation.

How do I fix or remediate CVE-2025-21853?

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-2025-21853?

CyberStrike's AI-powered security agents can automatically detect CVE-2025-21853 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.