Applied Cybernetics Group
Threat intel → detection pipeline
Friday, September 18, 2026
Data as of 13:09 UTC

Red Hat Libuser Race Condition Vulnerability

Added to KEV
2026-08-26
Federal due date
2026-09-09
Vendor
Red Hat
Product
Libuser
EPSS
94.9th percentile (score 0.088, as of 2026-09-16)
NVD CVSS v3.1
5.1 (MEDIUM)
Ransomware use
Unknown
Upstream
https://nvd.nist.gov/vuln/detail/CVE-2015-3246

CISA short description

Red Hat libuser contains a race condition vulnerability that allows authenticated local users to corrupt the /etc/passwd file to cause a denial of service or privilege escalation.

Required action

Apply mitigations in accordance with vendor instructions, ensuring compliance with CISA’s BOD 26-04 Prioritizing Security Updates Based on Risk (see URL in Notes) guidance and CISA’s “Forensics Triage Requirements” (see URL in Notes). Follow applicable BOD 26-04 guidance for cloud services or discontinue use of the product if mitigations are unavailable. Stakeholders are responsible for evaluating each asset's internet exposure and ensuring adherence to BOD 26-04 patching guidelines.

NVD description

libuser before 0.56.13-8 and 0.60 before 0.60-7, as used in the userhelper program in the usermode package, directly modifies /etc/passwd, which allows local users to cause a denial of service (inconsistent file state) by causing an error during the modification. NOTE: this issue can be combined with CVE-2015-3245 to gain privileges.

EPSS percentile is the FIRST.org exploit-probability ranking as of the date noted above; it moves daily. CVSS reflects NVD's analysis at time of publication.