VulnerabilityPublished 25 Jul 2026Updated 6 Nov 2026

CVE-2026-64306: Linux kernel · crypto: drbg – Fix returning success on failure in CTR_DRBG

Affects Linux kernelSource CVE Database V5

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Not known to be exploited · fixed in cc42fb40171c249bb859071d81b4eb007398a0bc : update Linux kernel when convenient.

Data as of 6 Nov 2026, 17:19 UTC

Severity

Unrated

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

Thin evidence

One scorer or none

Exploitation: No evidence of active exploitation and no public proof of concept
Automatable: Attackers cannot reliably automate steps 1–4 of the kill chain
Technical impact: Limited control over the software or limited information exposure

CISA SSVC assessment, 2026-11-06.

Patch

Available – fixed in cc42fb40171c249bb859071d81b4eb007398a0bc, bbbac12083eff489b35d848332f0dff311131344, a9e886f73dd717027028bb7e3bbca93601ecdfc7 +6

Exploitation evidence

Disclosed: evidence found.
CVE published 25 Jul 2026
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 6 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.

What to do

Upgrade to a fixed release listed under Affected software.

Affected software

Product	Affected	Fixed in
LinuxLinux	Affected >=3.12.44 <3.13	Fixed in cc42fb40171c249bb859071d81b4eb007398a0bc bbbac12083eff489b35d848332f0dff311131344 a9e886f73dd717027028bb7e3bbca93601ecdfc7 75597e8774f319152744d24e0683d9393540a951 074db6db03a0aaa78f05ca9d4838053713796665 39a31ad9e2a5ed7e9c9c6f711dca96c8c8f5f26b 23b8b188cb32e5531d0f8d3af9506f8959cb369e 7b03312491f9fe6ba4d60c4023e7e61d2d1fed96 3.13
LinuxLinux	Affected =4.1	Fixed in–

Description

In the Linux kernel, the following vulnerability has been resolved: crypto: drbg - Fix returning success on failure in CTR_DRBG drbg_ctr_generate() sometimes returns success when it fails, leaving the output buffer uninitialized. Fix it.

References

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