VulnerabilityPublished 9 Nov 2025

CVE-2025-40109: Linux kernel · crypto: rng – Ensure set_ent is always present

Source GCVE Database

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Not known to be exploited.

Data as of 4 Nov 2026, 19:00 UTC

Severity

Unrated

Rated by Threat Radar · No CVSS score from NVD or the CNA

Exploitation evidence

Disclosed: evidence found.
CVE published 9 Nov 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 4 Nov 2026.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponized: A Metasploit exploit module or Exploit-DB entry exists (Metasploit scanner modules do not count), or CISA SSVC or the CVSS exploit maturity reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

ghsa-r2qx-8vq2-jc32

What to do

AI-suggested

A fix has been implemented in the Linux kernel to ensure set_ent is always present in the crypto rng subsystem. Users should apply the official kernel updates that include this fix once available.

Description

A vulnerability in the Linux kernel's cryptographic random number generator (rng) component was addressed by ensuring the set_ent function is always present. This fix resolves an issue where only the deterministic random bit generator (drbg) provided set_ent, potentially leading to inconsistent behavior.

Impact

The vulnerability could lead to inconsistent or improper entropy setting in the kernel's random number generation, which may affect cryptographic operations relying on rng. However, no specific exploitation or impact details are provided.

Summary

CVE-2025-40109 concerns the Linux kernel's crypto rng subsystem. The vulnerability involved the absence of the set_ent function except in the drbg implementation. The resolution ensures that set_ent is always set, preventing potential issues arising from its absence in other rng implementations.

References

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