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CVE-2025-21889

7.8 · HIGH
Published Mar 27, 2025 linux EPSS 0.20% (10th pctl)

Overview

CVE-2025-21889 is a high-severity vulnerability affecting linux linux_kernel. It was published on March 27, 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:

perf/core: Add RCU read lock protection to perf_iterate_ctx()

The perf_iterate_ctx() function performs RCU list traversal but

currently lacks RCU read lock protection. This causes lockdep warnings

when running perf probe with unshare(1) under CONFIG_PROVE_RCU_LIST=y:

WARNING: suspicious RCU usage

kernel/events/core.c:8168 RCU-list traversed in non-reader section!!

Call Trace:

lockdep_rcu_suspicious

? perf_event_addr_filters_apply

perf_iterate_ctx

perf_event_exec

begin_new_exec

? load_elf_phdrs

load_elf_binary

? lock_acquire

? find_held_lock

? bprm_execve

bprm_execve

do_execveat_common.isra.0

__x64_sys_execve

do_syscall_64

entry_SYSCALL_64_after_hwframe

This protection was previously present but was removed in commit

bd2756811766 ("perf: Rewrite core context handling"). Add back the

necessary rcu_read_lock()/rcu_read_unlock() pair around

perf_iterate_ctx() call in pe

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 >= 6.2, < 6.6.81 Affected

Frequently Asked Questions

What is CVE-2025-21889?

CVE-2025-21889 is a high-severity vulnerability affecting linux linux_kernel. It was published on March 27, 2025 and has a CVSS 3.1 base score of 7.8 (HIGH).

How severe is CVE-2025-21889?

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-2025-21889?

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-2025-21889?

CyberStrike's AI-powered security agents can automatically detect CVE-2025-21889 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.