CVE-2015-3246
Red Hat Libuser Race Condition Vulnerability
Red Hat Libuser
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.
Exploitation status
CISA Known Exploited Vulnerabilities
Listed by CISA on 26 August 2026. US federal agencies were required to remediate it by 9 September 2026.
EPSS — exploitation probability
FIRST puts the probability of exploitation activity in the next 30 days at 8.8%, which is higher than 94.9% of all scored vulnerabilities. EPSS is a forecast of activity, not a measure of severity, and it is rescored daily.
CVSS vector
CVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H
Frequently asked questions
Is CVE-2015-3246 being exploited by ransomware groups?
No ransomware group in this database is currently recorded as exploiting CVE-2015-3246.
What does CVE-2015-3246 affect?
CVE-2015-3246 affects Red Hat Libuser. 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.
How severe is CVE-2015-3246?
CVE-2015-3246 is rated MEDIUM with a CVSS base score of 5.1. EPSS puts the probability of exploitation in the next 30 days at 8.8%, higher than 94.9% of all scored vulnerabilities. It is listed in the CISA Known Exploited Vulnerabilities catalog, with a federal remediation deadline of 9 September 2026.
How should organisations respond to CVE-2015-3246?
Apply the vendor patch for Red Hat Libuser as the first priority, and treat any internet-facing instance as the most urgent. Because this vulnerability is associated with ransomware activity, also review whether the affected systems were reachable before patching, rather than assuming that patching alone closes the incident.