CVE-2015-3246
Red Hat Libuser Race Condition Vulnerability
Does this matter?
Known to be exploited in the wild (CISA KEV, CISA remediation deadline 9 September 2026). Treat as an emergency change: patch or isolate now, then hunt for prior compromise.
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.
- CVSS 3.1
- 5.1 MEDIUMCVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H
- EPSS
- 8.80% probability · 95th percentile
- CISA KEV
- Listed 26 August 2026 · due 9 September 2026
- Weakness
- CWE-264, CWE-367
- Affected
- redhat/enterprise linux · opensuse/opensuse · libuser project/libuser
- Source
- secalert@redhat.com
CISA notes
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. This vulnerability affects an open-source component, third-party library, protocol, or proprietary implementation that could be used by different products. For more information, please see: https://access.redhat.com/articles/1537873 ; BOD 26-04: https://www.cisa.gov/news-events/directives/bod-26-04-prioritizing-security-updates-based-risk ; Forensics Triage Requirements: https://www.cisa.gov/news-events/directives/bod-26-04-implementation-guidance-prioritizing-security-updates-based-risk ; https://nvd.nist.gov/vuln/detail/CVE-2015-3246
References
- http://lists.fedoraproject.org/pipermail/package-announce/2015-August/163044.htmlBroken Link
- http://lists.fedoraproject.org/pipermail/package-announce/2015-July/162947.htmlBroken Link
- http://lists.opensuse.org/opensuse-security-announce/2015-08/msg00000.htmlMailing List, Third Party Advisory
- http://rhn.redhat.com/errata/RHSA-2015-1482.htmlVendor Advisory
- http://rhn.redhat.com/errata/RHSA-2015-1483.htmlVendor Advisory
- http://www.securityfocus.com/bid/76022Third Party Advisory
- http://www.securitytracker.com/id/1033040Third Party Advisory
- https://access.redhat.com/articles/1537873Mitigation, Vendor Advisory
- https://www.exploit-db.com/exploits/44633/Third Party Advisory, VDB Entry
- https://www.qualys.com/2015/07/23/cve-2015-3245-cve-2015-3246/cve-2015-3245-cve-2015-3246.txtExploit
- http://lists.fedoraproject.org/pipermail/package-announce/2015-August/163044.htmlBroken Link
- http://lists.fedoraproject.org/pipermail/package-announce/2015-July/162947.htmlBroken Link
- http://lists.opensuse.org/opensuse-security-announce/2015-08/msg00000.htmlMailing List, Third Party Advisory
- http://rhn.redhat.com/errata/RHSA-2015-1482.htmlVendor Advisory
- http://rhn.redhat.com/errata/RHSA-2015-1483.htmlVendor Advisory
- http://www.securityfocus.com/bid/76022Third Party Advisory
- http://www.securitytracker.com/id/1033040Third Party Advisory
- https://access.redhat.com/articles/1537873Mitigation, Vendor Advisory
- https://www.exploit-db.com/exploits/44633/Third Party Advisory, VDB Entry
- https://www.qualys.com/2015/07/23/cve-2015-3245-cve-2015-3246/cve-2015-3245-cve-2015-3246.txtExploit
- https://blog.talosintelligence.com/uat-10147-chinese-speaking-adversary-integrates-agentic-ai-into-post-compromise-operations/Third Party Advisory
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2015-3246US Government Resource
Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.