Red Hat Libuser Race Condition
CVE-2015-3246 is a high-severity vulnerability in Enterprise Linux from Red Hat, with a CVSS 2.0 base score of 7.2 out of 10. It can be exploited with local access to the system by an unauthenticated attacker, without any action from a user. Affected Enterprise Linux versions: 5.0; 6.0; 7.0. The record does not name a fixed version, so check the vendor advisory. CISA added it to the Known Exploited Vulnerabilities catalogue on August 26, 2026, which means attacks have been observed in the wild.
Attackers are already exploiting this vulnerability, according to CISA.
What to do
- Update Libuser to 0.56.13-8 or 0.60-7, whichever matches your release line, or a later version.
- CISA's 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.
- Read the advisory on rhn.redhat.com for workarounds and exact fixed builds.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Red Hat | Enterprise Linux | 5.0; 6.0; 7.0 | Not stated |
| openSUSE | Opensuse | 13.2 | Not stated |
| Libuser Project | Libuser | before 0.56.13-8; 0.60 up to, but not including, 0.60-7 | 0.56.13-8, 0.60-7 |
Version data comes from NVD's product matching. Confirm against the vendor advisory before deciding you are unaffected.
How the severity score breaks down
- Access vector
- LocalLocal access is required.
- Access complexity
- LowNo special conditions are needed.
- Authentication
- NoneNo login is needed.
- Confidentiality
- CompleteAll data can be read.
- Integrity
- CompleteAny data can be modified.
- Availability
- CompleteThe system can be shut down completely.
Vector: AV:L/AC:L/Au:N/C:C/I:C/A:C. Scored by NVD.
| Scoring system | Score | Severity | Scored by |
|---|---|---|---|
| CVSS 3.1 | 7.4 | High | CISA (ADP) |
| CVSS 2.0 | 7.2 | High | NVD |
Official 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.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
Timeline
- CVE record published.
- Added to CISA's Known Exploited Vulnerabilities catalogue.
- CISA published its SSVC assessment (exploitation: active, automatable: no, technical impact: total).
- Deadline for US federal agencies to remediate, set by CISA.
- Record last changed materially (score, affected products, status or references).
References
Advisories
Third-party and government advisories
- lists.opensuse.org/opensuse-security-announce/2015-08/msg00000.htmlMailing List, Third Party Advisory
- securityfocus.com/bid/76022Third Party Advisory
- securitytracker.com/id/1033040Third Party Advisory
- exploit-db.com/exploits/44633/Third Party Advisory, VDB Entry
- blog.talosintelligence.com/uat-10147-chinese-speaking-adversary-integrates-agentic-ai-into-post-compromise-op…Third Party Advisory
- cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2015-3246US Government Resource
Technical write-ups (may include proof of concept)
Other vulnerabilities in Enterprise Linux
- 8.1 High severity
- 9.8 Critical severity
- 8.6 High severity
- 8.6 High severity
- 8.2 High severity
- 8.6 High severity
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