CVE-2026-64306: crypto: drbg - Fix returning success on failure in CTR_DRBG

mediumCVSS 5.5CVE-2026-64306

CSIRTS triage

vendor: Linux product: CryptoOther

What: The CTR_DRBG function incorrectly returns success on failure.
Who is affected: Deployments using the crypto subsystem.
Urgency: Remediation is necessary to ensure proper functionality, though no exploitation is reported.
Action: Apply the latest patches for the crypto subsystem.

AI-assisted analysis generated from the source advisory — verify against the original.

⚡ Watch Crypto

Get an email when a new Crypto advisory drops — max one per day, one-click unsubscribe.

Details

Source: Microsoft Security Response Center (INTL · vendor-psirt · site)
Severity: medium — CVSS 5.5
Published: 2026-08-06
Exploitation: Not in CISA KEV at last sync

Original advisory: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-64306

Exploitation outlook

EPSS (FIRST.org) estimates each CVE’s probability of exploitation in the next 30 days — here is the CSIRTS.com read on those numbers.

Low exploitation riskCVE-2026-643060.22% 30-day exploitation probability — currently an unlikely target, but scores change as exploit code circulates. Riskier than 12% of all EPSS-scored CVEs.

Referenced CVEs

CVE	CSIRTS overview	External
CVE-2026-64306	coverage & exploitation status	NVD · CVE.org

Same CVEs, other sources

How other CERTs, PSIRTs and databases cover the vulnerabilities in this advisory.

unknownCVE-2026-64306: In the Linux kernel, the following vulnerability has been resolved: crypto: drbg - Fix returni…nvd

Recent advisories for crypto

A cluster of recent advisories against the same product widens the attack surface — attackers routinely chain freshly published CVEs on one product, so review these together.

unknownCVE-2026-78369: RansomLook contains a missing authentication vulnerability in the /admin/crypto/group/new endp…nvd · 2026-08-24
medium[UPDATE] [medium] Golang Go-Module (Net, Image, Crypto): Multiple Vulnerabilitiescert-bund · 2026-08-24
mediumCVE-2026-45271: Picotls is a TLS protocol library that allows users select different crypto backends based on …nvd · 2026-08-21
mediumCVE-2026-5224: Cleartext storage of sensitive information vulnerability in Kriptok Crypto and Information Tech…nvd · 2026-08-18
highCVE-2026-74578: In the Linux kernel, the following vulnerability has been resolved: crypto: algif_skcipher - f…nvd · 2026-08-16
highCVE-2026-74438: In the Linux kernel, the following vulnerability has been resolved: crypto: sun4i-ss - Remove …nvd · 2026-08-15