Vulnerability in Linux
CVE-2025-21840
In the Linux kernel, the following vulnerability has been resolved: thermal/netlink: Prevent userspace segmentation fault by adjusting UAPI header The intel-lpmd tool [1], which uses the THERMAL_GENL_ATTR_CPU_CAPABILITY attribute to receive HFI events from kernel space, encounters a segmentation fault after commit 1773572863c4 ("thermal: netlink: Add the commands and the events for the thresholds"). The issue arises because the THERMAL_GENL_ATTR_CPU_CAPABILITY raw value was changed while intel_lpmd still uses the old value. Although intel_lpmd can be updated to check the THERMAL_GENL_VERSION and use the appropriate THERMAL_GENL_ATTR_CPU_CAPABILITY value, the commit itself is questionable. The commit introduced a new element in the middle of enum thermal_genl_attr, which affects many existing attributes and introduces potential risks and unnecessary maintenance burdens for userspace thermal netlink event users. Solve the issue by moving the newly introduced THERMAL_GENL_ATTR_TZ_PREV_TEMP attribute to the end of the enum thermal_genl_attr. This ensures that all existing thermal generic netlink attributes remain unaffected. [ rjw: Subject edits ]
EPSS: 0.002 (10.7th percentile) — read the EPSS interpretation.
CVSS v3 metric
CVSS v3 base score 5.5 (Medium). Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H.
Affected products
- Linux — versions 1773572863c43a14a3e45f0591f28b7dec1ee52a, 6.13, 0
- Linux Linux_kernel — versions 6.14
Public proof-of-concept exploits
References
Frequently asked questions
- What is CVE-2025-21840?
- CVE-2025-21840 is a medium-severity vulnerability in Linux. CVSS score: 5.5/10. Published 2025-03-07.
- How severe is CVE-2025-21840?
- Medium severity. CVSS v3 base score is 5.5 out of 10.
- Is CVE-2025-21840 known to be exploited?
- 1 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.