How severe is CVE-2015-3246?

No CVSS score has been assigned to CVE-2015-3246 yet. Review the advisory details and affected package list to assess your exposure.

Which packages are affected by CVE-2015-3246?

Affected package information for CVE-2015-3246 is not yet fully mapped. Check the official advisory links for details.

How do I fix CVE-2015-3246?

No fixed release is recorded for CVE-2015-3246 yet. Track the upstream advisory, and apply the exposure-reduction steps below in the meantime.

How do I detect CVE-2015-3246 in my code and dependencies?

Identify every host running the affected component and compare the installed build against the fixed version below — for source-built or distro-packaged software the version string, not a lockfile, is the source of truth (`dpkg -l`, `rpm -q`, or the binary's own `--version`).

How do I mitigate CVE-2015-3246 if there is no patch (or I can't update yet)?

Cap what an attacker can consume: apply request size, rate and timeout limits in front of the affected component, and run it with memory and CPU limits so exhaustion degrades one worker rather than the whole service.

Is CVE-2015-3246 actively exploited in the wild?

Yes. There are 4 known exploit references for CVE-2015-3246, including 2 documented proof-of-concept exploits on Exploit-DB and 2 in-the-wild exploitations observed on GitHub and other sources. Treat this as actively exploitable and prioritize patching immediately. All exploit code should only be run in an isolated sandbox environment for research or authorized testing — never against production systems without explicit written authorization.

What is the EPSS score for CVE-2015-3246?

CVE-2015-3246 has an EPSS (Exploit Prediction Scoring System) score of 8.4%, placing it in the 95th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. This score indicates relatively lower exploitation probability, though the CVSS severity should still guide your patching priority.

Is CVE-2015-3246 in the CISA Known Exploited Vulnerabilities catalog?

Yes. CVE-2015-3246 (Red Hat Libuser Race Condition Vulnerability) was added to CISA's Known Exploited Vulnerabilities (KEV) catalog on 2026-08-26. CISA required all US federal civilian agencies to remediate this vulnerability by 2026-09-09. The required action was: 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. Being listed in the KEV catalog is the strongest possible confirmation of active exploitation — treat this as a critical priority.

What type of vulnerability is CVE-2015-3246?

CVE-2015-3246 is classified as CWE-264 (CWE-264), CWE-367 (CWE-367). These weakness types describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation.

Is there exploit tooling available for CVE-2015-3246?

A Metasploit module references CVE-2015-3246, which lowers the barrier to weaponization. Public exploit tooling significantly increases real-world risk — prioritize patching and ensure detection coverage. Exploit tooling should only ever be used in isolated, authorized testing environments.

When was CVE-2015-3246 published, and has it been updated?

CVE-2015-3246 was published on August 11, 2015 and was last updated on April 16, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

CISA KEV · ACTIVELY EXPLOITED

CVE-2015-3246 — Red Hat

CVE-2015-3246 is a CWE-264 vulnerability. It is in CISA's Known Exploited Vulnerabilities catalog (added 2026-08-26) — treat it as actively exploited and patch now. No vendor fix is recorded yet; mitigation options are listed below.

Published

Aug 11, 2015

Updated

Apr 16, 2026

Affected

3 products

Patched

See advisory

Exploits

4 known

Exploitation data as of Oct 9, 2026 · OSV.dev, NVD, CISA KEV, FIRST.org (EPSS)

Exploitation Status

Actively exploited in the wild

Confirmed by CISA's Known Exploited Vulnerabilities catalog on 2026-08-26. Federal agencies were required to remediate by 2026-09-09.
A successful exploit gives an attacker total control of the affected component, not partial access.

Exploitation and automatability from CISA (KEV catalog and SSVC triage) for CVE-2015-3246.

EPSS Exploitation Probability

via FIRST.org ↗

8.4%probability of exploitation in next 30 days

Lower Risk-0.37%

Lower risk than most CVEs95th percentile — riskier than 95% of all scored CVEsHighest risk

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

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.

Affected Products

3 products · 6 configurations

Application

libuserlibuser_project

≥ 0.60 && < 0.60-7

range

opensuseopensuse

1 version

13.2

enterprise linuxredhat

3 versions

5.06.07.0

Exploits & PoCs

Research use only. For defensive security, authorized penetration testing, and academic research only. Never execute exploit code against systems without explicit written authorization.

EDB-37706doslinux✓ Verified

Libuser Library - Multiple Vulnerabilities

by Qualys Corporation · Jul 27, 2015

Exploit-DB Source

EDB-44633locallinux✓ Verified

Libuser - 'roothelper' Local Privilege Escalation (Metasploit)

by Metasploit · May 16, 2018

Exploit-DB Source

Detection & mitigation playbook

Vulnerability

Detect
Identify every host running the affected component and compare the installed build against the fixed version below — for source-built or distro-packaged software the version string, not a lockfile, is the source of truth (`dpkg -l`, `rpm -q`, or the binary's own `--version`).
Remediation status
No fixed release is recorded for CVE-2015-3246 yet. Track the upstream advisory, and apply the exposure-reduction steps below in the meantime.
Mitigate without a patch
Cap what an attacker can consume: apply request size, rate and timeout limits in front of the affected component, and run it with memory and CPU limits so exhaustion degrades one worker rather than the whole service.

Fixing This On Your OS

If you run this on a Linux distribution, patch through your package manager against the distro's own security advisory below — it tracks the exact backported fix for your release, which can ship on a different timeline (and sometimes a different severity) than the upstream project.

Red HatImportant

This issue affects the versions of libuser as shipped with Red Hat Enterprise Linux 5. Red Hat Enterprise Linux 5 is now in Production 3 Phase of the support and maintenance life cycle. This vulnerability has been rated as having Important security impact and is not currently planned to be addressed in future updates.…

Workaround published by Red Hat

Add pam_warn and pam_deny rules to /etc/pam.d/chfn and /etc/pam.d/chsh to prevent non-root users from using this functionality. With these edits, the files should contain: auth sufficient pam_rootok.so auth required pam_warn.so auth required pam_deny.so auth include system-auth account include system-auth password include system-auth session include system-auth After these changes, attempts by unprivileged users to use chfn and chsh (and the respective functionality in the userhelper program) will fail, and will be logged (by default in /var/log/secure).

Source: Red Hat security advisory for CVE-2015-3246 (CC BY 4.0)

Product	Fixed in	Advisory
Red Hat Enterprise Linux 6	`libuser-0:0.56.13-8.el6_7`	RHSA-2015:1482
Red Hat Enterprise Linux 7	`libuser-0:0.60-7.ael7b_1`	RHSA-2015:1483

Frequently Asked Questions

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