CVE-2025-21841: Linux kernel · cpufreq/amd-pstate: Fix cpufreq_policy ref counting
Affects Linux kernelSource GCVE Database
Not known to be exploited · CVSS 5.5 Medium.
Data as of 29 Oct 2026, 23:42 UTC
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:HExploitation evidence
Disclosed: evidence found.
CVE published 7 Mar 2025
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 29 Oct 2026.
What to do
Affected software
| Product | Affected | Fixed in |
|---|---|---|
Ubuntu 24.04 LTSlinux-raspi-realtimepkg:deb/ubuntu/linux-raspi-realtime?arch=source&distro=nobleOther threats | Affected
| Fixed in– |
Ubuntu 24.04 LTSlinux-realtimepkg:deb/ubuntu/linux-realtime?arch=source&distro=nobleOther threats | Affected
| Fixed in– |
Ubuntu 22.04 LTSlinux-allwinner-5.19pkg:deb/ubuntu/linux-allwinner-5.19?arch=source&distro=jammyOther threats | Affected
| Fixed in– |
Ubuntu 22.04 LTSlinux-aws-5.19pkg:deb/ubuntu/linux-aws-5.19?arch=source&distro=jammyOther threats | Affected
| Fixed in– |
Ubuntu 22.04 LTSlinux-aws-6.2pkg:deb/ubuntu/linux-aws-6.2?arch=source&distro=jammyOther threats | Affected
| Fixed in– |
Ubuntu 22.04 LTSlinux-aws-6.5pkg:deb/ubuntu/linux-aws-6.5?arch=source&distro=jammyOther threats | Affected
| Fixed in– |
Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.
AI-suggested
A fix is available for this vulnerability. Users should apply the updated Linux kernel versions that include the corrected reference counting in the amd_pstate driver. Specific affected versions are listed and should be upgraded to patched releases. No additional mitigation steps are indicated.
Description
A vulnerability in the Linux kernel's cpufreq/amd-pstate driver was fixed to correct improper reference counting of cpufreq_policy objects. The function amd_pstate_update_limits() took a cpufreq_policy reference but failed to decrement the reference count on one exit path, potentially leading to resource management issues. This flaw affects multiple specific Linux kernel versions used in Ubuntu distributions.
References
- ubuntu.com/security/CVE-2025-21841 (opens in a new tab)
- cve.org/CVERecord?id=CVE-2025-21841 (opens in a new tab)
- git.kernel.org/linus/3ace20038e19f23fe73259513f1f08d4bf1a3c83 (opens in a new tab)
- git.kernel.org/stable/c/28e4c515cf644c621800bd97841757fd49891ba4 (opens in a new tab)
- git.kernel.org/stable/c/3ace20038e19f23fe73259513f1f08d4bf1a3c83 (opens in a new tab)
- git.kernel.org/stable/c/56e6976793c0fcf1638aa534242408ab4e4ca705 (opens in a new tab)