Red Hat Enterprise Linux's Libuser Race Condition in Password File Writes Allows Local Attackers to Corrupt System Files; CISA's September 9th KEV Deadline Has Passed

Last refreshed2026-09-27

Status: KEV | Advisory ID: CVE-2015-3246

Key Details

CVE	CVE-2015-3246
Vulnerability Name	Red Hat Libuser Race Condition Vulnerability
CVSS Score / Version	5.1 (Medium) / CVSS v3.1
Updated	2026-09-22
CVSS Vector	`CVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H`
CVSS Prose	attack vector is local; attack complexity is high; privileges required is none; user interaction is none; scope is unchanged; confidentiality impact is none; integrity impact is none; availability impact is high.
Affected products	Red Hat - duplicate Libuser, Red Hat Enterprise Linux, opensuse openSUSE, libuser_project libuser, and Red Hat Libuser
Exploitation status	Listed in CISA's Known Exploited Vulnerabilities (KEV) catalog, indicating confirmed active exploitation.
KEV listing	Added to CISA's Known Exploited Vulnerabilities (KEV) catalog on 2026-08-26.
Exploitation prediction (EPSS)	8.80% probability of exploitation in the next 30 days (95% percentile) -- FIRST.org's EPSS model.
Federal remediation deadline	2026-09-09 (CISA KEV, Binding Operational Directive).

Affected Products, Subsystems & Sectors

Vendor	Product	Affected Versions	Patch Status
Red Hat - duplicate	Libuser
Red Hat	Enterprise Linux
opensuse	openSUSE
libuser_project	libuser
Red Hat	Libuser

Vendor

Product

Affected Versions

Patch Status

Red Hat - duplicate

Libuser

Red Hat

Enterprise Linux

opensuse

openSUSE

libuser_project

libuser

Red Hat

Libuser

Subsystems	EWS Workstation Delivery/Virtualization
Sectors	All Sectors

What to Know

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.

What to Do

Monitor Red Hat - duplicate, Red Hat, opensuse, and libuser_project's web pages for any future patch releases.

References

Source	Reference
NVD	https://nvd.nist.gov/vuln/detail/CVE-2015-3246
CVE	https://www.cve.org/CVERecord?id=CVE-2015-3246

Source

Reference

NVD

https://nvd.nist.gov/vuln/detail/CVE-2015-3246

CVE

https://www.cve.org/CVERecord?id=CVE-2015-3246

KEV Required Action

Field	Value
KEV Link	https://www.cisa.gov/known-exploited-vulnerabilities-catalog
Date Added to KEV	2026-08-26
Required Action Due Date	2026-09-09
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.

Field

Value

KEV Link

https://www.cisa.gov/known-exploited-vulnerabilities-catalog

Date Added to KEV

2026-08-26

Required Action Due Date

2026-09-09

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.