CVE-2025-40109: Linux kernel · crypto: rng – Ensure set_ent is always present
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, 14:05 UTC
Rated by Threat Radar · No CVSS score from NVD or the CNA
- EPSS
- 0.2% chance of exploitation in 30 days – higher than 12% 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 +64
Exploitation evidence
Disclosed: evidence found.
CVE published 9 Nov 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@6.17.0-7.7?arch=source&distro=questingOther threats | Affected
| Fixed in
|
Ubuntu 25.10linux-awspkg:deb/ubuntu/linux-aws@6.17.0-1004.4?arch=source&distro=questingOther threats | Affected
| Fixed in
|
Ubuntu 25.10linux-azurepkg:deb/ubuntu/linux-azure@6.17.0-1006.6?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@6.17.0-1004.4?arch=source&distro=questingOther threats | Affected
| Fixed in
|
Ubuntu 25.10linux-oraclepkg:deb/ubuntu/linux-oracle@6.17.0-1005.5?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.
Description
In the Linux kernel, the following vulnerability has been resolved: crypto: rng - Ensure set_ent is always present Ensure that set_ent is always set since only drbg provides it.
References
- ubuntu.com/security/CVE-2025-40109 (opens in a new tab)
- cve.org/CVERecord?id=CVE-2025-40109 (opens in a new tab)
- git.kernel.org/linus/c0d36727bf39bb16ef0a67ed608e279535ebf0da (opens in a new tab)
- git.kernel.org/stable/c/15d6f42da1bb527629d8e1067b1302d58dec9166 (opens in a new tab)
- git.kernel.org/stable/c/17acbcd44fe8dc17dc1072375e76df2d52da6ac8 (opens in a new tab)
- git.kernel.org/stable/c/915cb75983bc5e8b80f8a2f25a4af463f7b18c14 (opens in a new tab)
- git.kernel.org/stable/c/ab172f4f42626549b02bada05f09e3f2b0cc26ec (opens in a new tab)
- git.kernel.org/stable/c/bd903c25b652c331831226cdf56c8179d18e43f4 (opens in a new tab)
- git.kernel.org/stable/c/c0d36727bf39bb16ef0a67ed608e279535ebf0da (opens in a new tab)
- git.kernel.org/stable/c/c5c703b50e91dd4748769f4c5ab50d9ad60be370 (opens in a new tab)
- git.kernel.org/stable/c/e247a7d138e514a40edda7c4d72c8bd49bb2cad3 (opens in a new tab)
- ubuntu.com/security/notices/USN-7906-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-7906-2 (opens in a new tab)
- ubuntu.com/security/notices/USN-7906-3 (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-8033-5 (opens in a new tab)