VulnTideExploited vulnerabilities, by vendor. Data as of 28 Oct 2026.
Known exploitedIn CISA's KEV catalog since 26 August 2026Ransomware use: unknown
Red Hat Libuser

CVE-2015-3246: Red Hat Libuser Race Condition Vulnerability

Is it exploited?

Yes. CISA added it to the Known Exploited Vulnerabilities catalog on 26 Aug 2026, 4,033 days after the CVE record was published.

How likely is exploitation in the next 30 days?
8.5%

EPSS score, percentile 95 of all scored records

How severe?
7.4 High

CVSS v3.1 base score, from CISA's enrichment of the record

What should I do?

Required action (CISA), due 9 Sep 2026: 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.

Advisories and patches (5)

Which versions are affected?

Not stated. The CVE record gives vendor and product as “n/a” and the version as “unspecified”.

Source: CISA Known Exploited Vulnerabilities (KEV) catalog, 2026.10.28, as of 28 Oct 2026; FIRST Exploit Prediction Scoring System (EPSS), v2026.06.15, as of 28 Oct 2026; CVE List V5 (CVE Program), cve_2026-10-28_0000Z, as of 28 Oct 2026. About the data.

What to do

Required action, set by CISA

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.

CISA due date for this action: 9 September 2026.

Advisories and patches

Linked from CISA's catalog entry

Affected products and versions

The CVE record does not name affected products or versions: vendor and product are “n/a” and the version is “unspecified”.

Source: CVE List V5 (CVE Program), cve_2026-10-28_0000Z, as of 28 Oct 2026. About the data.

About this vulnerability

Red Hat libuser contains a race condition vulnerability that allows authenticated local users to corrupt the /etc/passwd file to cause a denial of service or privilege escalation.

Summary: CISA's KEV catalog, as of 28 Oct 2026.

  • CISA added CVE-2015-3246 to its Known Exploited Vulnerabilities (KEV) catalog on 26 Aug 2026.
  • CISA's ransomware flag for this entry is "Unknown": no evidence of ransomware use in the catalog, which is not proof of none.
  • The due date CISA sets for the required action is 9 Sep 2026.
  • The CVE record was published on 11 Aug 2015, 4,033 days before it was added to KEV.
  • The CVE record carries a CVSS v3.1 base score of 7.4 (High), taken from CISA's enrichment of the record.
  • FIRST's EPSS model puts the probability of exploitation in the next 30 days at 8.5% (percentile 95), as of 28 Oct 2026.
  • CISA's SSVC assessment in the CVE record: exploitation active, automatable no, technical impact total.

Source: CISA Known Exploited Vulnerabilities (KEV) catalog, 2026.10.28, as of 28 Oct 2026; CVE List V5 (CVE Program), cve_2026-10-28_0000Z, as of 28 Oct 2026; FIRST Exploit Prediction Scoring System (EPSS), v2026.06.15, as of 28 Oct 2026. About the data.

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: CVE List V5 (CVE Program), cve_2026-10-28_0000Z, as of 28 Oct 2026. About the data.

Weakness

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

CWE and CAPEC are maintained by MITRE; the entries are those named in the CVE record and the KEV entry.

Timeline

DateEvent
11 Aug 2015CVE record published
26 Aug 2026Added to CISA KEV
9 Sep 2026CISA due date for the required action
1 Oct 2026CVE record last updated

References

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