Vulnerability report

Exploited in the wild Confirmed confidence In CISA KEV

CVE-2015-3246

libuser Denial of Service

Red Hat, Opensuse, Libuser_project / libuser

Watch CVE-2015-3246 Browse KEV feed
Severity
CVSS 7.4 · High
Confidence
Confirmed
Exploit status
Exploited in the wild
EPSS
8.4%
First observed
—
Last observed
—

Decision summary

What security teams need to know first

Direct answers before the deeper technical record.

What it is

CVE-2015-3246 is an unauthenticated vulnerability affecting Red Hat, Opensuse, Libuser_project libuser. libuser before 0.56.13-8 and 0.60 before 0.60-7, as used in the userhelper program in the usermode package,...

Is it exploited?

Yes. Previdian tracks this CVE as a known exploited vulnerability. Confidence is confirmed. Listed in CISA KEV. Also confirmed by third-party sources.

Who is affected?

Red Hat, Opensuse, Libuser_project / libuser.

What should we do?

Prioritize remediation. Validate affected assets and apply vendor fixes on an accelerated timeline.

Overview

libuser Denial of Service

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.

View vendor advisory (opens in new tab)
Published
11 Aug 2015
Exploitation Reported
26 Aug 2026
Attack vector
Local
Complexity
High
Privileges
None
User interaction
None

Tags

cisa

CVE References

  • CVE Record CVE.org · CVE Record https://www.cve.org/CVERecord?id=CVE-2015-3246
  • FEDORA-2015-12301 lists.fedoraproject.org · Vendor Advisory http://lists.fedoraproject.org/pipermail/package-announce/2015-July/1...
  • RHSA-2015:1482 rhn.redhat.com · Vendor Advisory http://rhn.redhat.com/errata/RHSA-2015-1482.html
  • FEDORA-2015-12064 lists.fedoraproject.org · Vendor Advisory http://lists.fedoraproject.org/pipermail/package-announce/2015-August...
  • openSUSE-SU-2015:1332 lists.opensuse.org · Vendor Advisory http://lists.opensuse.org/opensuse-security-announce/2015-08/msg00000...
  • RHSA-2015:1483 rhn.redhat.com · Vendor Advisory http://rhn.redhat.com/errata/RHSA-2015-1483.html
  • 44633 exploit-db.com · Exploit https://www.exploit-db.com/exploits/44633/
  • 76022 securityfocus.com · VDB Entry http://www.securityfocus.com/bid/76022
  • 1033040 securitytracker.com · VDB Entry http://www.securitytracker.com/id/1033040
  • access.redhat.com/articles/1537873 access.redhat.com · CVE Record https://access.redhat.com/articles/1537873
  • qualys.com/2015/07/23/cve-2015-3245-cve-2015-3246/cve-2... qualys.com · CVE Record https://www.qualys.com/2015/07/23/cve-2015-3245-cve-2015-3246/cve-201...

Exploitation evidence

Why Previdian marks this CVE as exploited

Third-party attestation and first-party sensor observation are shown separately so teams can judge the evidence chain.

Exploited in the wild

CISA

Recorded 26 Aug 2026

A trusted third party reported exploitation.

Proof of concept available

CVE

Recorded 28 Apr 2025

Public scanner or PoC coverage increases practical exploitability.

Known exploited vulnerability sources

Per-source evidence links for KEV attestations are available through the Previdian Pro API.

Learn about Pro API access
Source Added
CISA First 2026-08-26 17:00 UTC
CVE 2026-08-26 18:01 UTC

Detection

Operational artifacts and observed signals

Make the evidence actionable in scanner, SOC, and edge-control workflows.

Observed signals

Request targets
User-Agents
Callback hosts
0
0
0

Request targets and User-Agents available in Pro. Callback host details available in Enterprise.

Virtual patch status

No Previdian virtual patch is currently available. Future rules ship for ModSecurity, Cloudflare, and AWS WAF.

Learn about virtual patches →

Scanner Artifacts

Scanner and exploit-framework references linked to this CVE.

Scanner Reference Detected
Metasploit https://github.com/rapid7/metasploit-framework/blob/master/modules/exploits/linux/local/libuser_roothelper_priv_esc.rb 28 Apr 2025

Risk and context

Severity, weaknesses, and research context

CVSS v3.1

7.4 High

Potential damage if exploited. Separate from whether attackers are using it.

CVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H

EPSS

8.4%

Estimated chance of exploitation in the next 30 days. Previdian's warning comes from evidence, not this score.

Weaknesses

Time-of-check Time-of-use (TOCTOU) Race Condition CWE-367

Recent mention · RecordedFuture

August 2026 CVE Landscape

In August 2026, Insikt Group® identified 73 high-impact vulnerabilities that should be prioritized for remediation, 43 of which had a Very Critical Recorded Future Risk Score. This represents a 14% decrease from last month.

Read full advisory

All CVSS Scores

CVSS v3.1 7.4 High

CVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H

CVSS v2.0 7.2 High

AV:L/AC:L/Au:N/C:C/I:C/A:C

Potential Proof of Concepts

These PoCs are unverified and could contain malware. Use at your own risk.

libuser_roothelper_priv_esc

metasploit · Created Unknown

Metasploit module for CVE-2015-3246

44633

cve · Created Unknown

Timeline

From disclosure to observed exploitation

  1. 18:01 UTC

    KEV confirmed by CVE

    Exploitation attested by an external source

  2. 17:00 UTC

    Added to CISA KEV

    Listed in the CISA Known Exploited Vulnerabilities catalog

  3. 15:02 UTC

    Metasploit module available

    Exploit module available

  4. 15:02 UTC

    Public PoC available

    Public proof-of-concept code published

  5. 14:00 UTC

    CVE published

    Vulnerability disclosed publicly

  6. 00:00 UTC

    CVE ID reserved

    Identifier reserved by the CNA

Pro API

Automate this intelligence

Confidence, exploit status, sensor telemetry, PoCs, scanner integrations, mentions, and tags are available programmatically for VM, SOC, and CTI workflows.

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  • Evidence confidence and provenance
  • First-party sensor telemetry
  • PoC and scanner references
  • Affected versions and enrichment
  • Automation-ready JSON delivery

GET /api/v2/pro/kevs/CVE-2015-3246

Free JSON includes basic KEV fields 
{
  "cve_id": "CVE-2015-3246",
  "confidence": "Confirmed",
  "cvss_score": 7.4,
  "cvss_estimated": false,
  "epss_score": 0.08434,
  "exploit_status": {
    "exploited_in_the_wild": true,
    "active_exploitation_observed": false
  },
  "sensor_telemetry": { "attempts": 0, "sensors": 0 }
}