CVE-2025-40346: Linux kernel · arch_topology: Fix incorrect error check in topology_parse_cpu_capacity()
Affects Linux kernelSource GCVE Database
Not known to be exploited · fixed in 5.15.0-1100.107~20.04.2 : update Linux kernel when convenient.
Data as of 26 Oct 2026, 13:47 UTC
Rated by Threat Radar · No CVSS score from NVD or the CNA
- EPSS
- 0.2% chance of exploitation in 30 days – higher than 10% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
- Patch
- Available – fixed in 5.15.0-1100.107~20.04.2, 5.15.0-1110.119~20.04.1, 5.15.0-1100.109~20.04.1 +67
Exploitation evidence
Disclosed: evidence found.
CVE published 16 Dec 2025
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: 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 26 Oct 2026.
What to do
Upgrade to a fixed release listed under Affected software.
Affected software
| Product | Affected | Fixed in |
|---|---|---|
Ubuntu 25.10linuxpkg:deb/ubuntu/linux@6.17.0-14.14?arch=source&distro=questingOther threats | Affected
| Fixed in
|
Ubuntu 25.10linux-awspkg:deb/ubuntu/linux-aws@6.17.0-1007.7?arch=source&distro=questingOther threats | Affected
| Fixed in
|
Ubuntu 25.10linux-azurepkg:deb/ubuntu/linux-azure@6.17.0-1008.8?arch=source&distro=questingOther threats | Affected
| Fixed in
|
Ubuntu 25.10linux-azure-fdepkg:deb/ubuntu/linux-azure-fde@6.17.0-1017.17?arch=source&distro=questingOther threats | Affected
| Fixed in– |
Ubuntu 25.10linux-gcppkg:deb/ubuntu/linux-gcp@6.17.0-1007.7?arch=source&distro=questingOther threats | Affected
| Fixed in
|
Ubuntu 25.10linux-oraclepkg:deb/ubuntu/linux-oracle@6.17.0-1007.7?arch=source&distro=questingOther 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
An official patch addressing this vulnerability is available and should be applied. The fix corrects the error checking logic in topology_parse_cpu_capacity() to prevent NULL pointer dereference. Users should update to the patched Linux kernel versions as provided by their distribution vendors. No additional mitigation is required beyond applying the official update.
Description
A vulnerability in the Linux kernel's arch_topology component caused an incorrect error check in the topology_parse_cpu_capacity() function. The flaw involved improper use of PTR_ERR_OR_ZERO(), which led to the code proceeding with NULL clock pointers and potentially causing a NULL pointer dereference in clk_get_rate(). This was fixed by replacing the check with !IS_ERR_OR_NULL() to ensure only valid pointers proceed. Multiple Linux kernel versions are affected, and an official patch is available.
References
- ubuntu.com/security/CVE-2025-40346 (opens in a new tab)
- cve.org/CVERecord?id=CVE-2025-40346 (opens in a new tab)
- git.kernel.org/linus/2eead19334516c8e9927c11b448fbe512b1f18a1 (opens in a new tab)
- git.kernel.org/stable/c/02fbea0864fd4a863671f5d418129258d7159f68 (opens in a new tab)
- git.kernel.org/stable/c/2eead19334516c8e9927c11b448fbe512b1f18a1 (opens in a new tab)
- git.kernel.org/stable/c/3373f263bb647fcc3b5237cfaef757633b9ee25e (opens in a new tab)
- git.kernel.org/stable/c/3a01b2614e84361aa222f67bc628593987e5cdb2 (opens in a new tab)
- git.kernel.org/stable/c/45379303124487db3a81219af7565d41f498167f (opens in a new tab)
- git.kernel.org/stable/c/64da320252e43456cc9ec3055ff567f168467b37 (opens in a new tab)
- git.kernel.org/stable/c/a77f8434954cb1e9c42c3854e40855fdcf5ab235 (opens in a new tab)
- ubuntu.com/security/notices/USN-8029-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8030-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8033-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8033-2 (opens in a new tab)
- ubuntu.com/security/notices/USN-8033-3 (opens in a new tab)
- ubuntu.com/security/notices/USN-8034-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8033-4 (opens in a new tab)
- ubuntu.com/security/notices/USN-8029-2 (opens in a new tab)
- ubuntu.com/security/notices/USN-8033-5 (opens in a new tab)
- ubuntu.com/security/notices/USN-8034-2 (opens in a new tab)