What is CVE-2015-3246?

CVE-2015-3246 is Red Hat Libuser Race Condition Vulnerability. The supplied enrichment data classifies it as Race Condition mapped to CWE-264 CWE-264; CWE-367 CWE-367.

Which versions are affected?

Affected product and version evidence is listed in the product table above. Current public advisories should be checked for exact version scope before patch targeting is finalized.

Is there active exploitation?

Yes: CISA KEV signal present. If exploitation is not confirmed from current sources, teams should document that status and continue monitoring KEV, vendor, and telemetry updates.

Is there a public exploit?

7 public PoC repositories reported; 1 marked weaponized in current dataset. Public exploit or PoC availability should raise triage priority, especially for exposed or business-critical systems.

How can defenders detect it?

Start with Not reported where available. Look for vulnerability-class behavior, product errors, suspicious authentication events, exploit probes, and abnormal process activity based only on evidence that applies to the affected product.

How should teams prioritize it?

Prioritize CVE-2015-3246 using CVSS 7.2, EPSS 9%, KEV status, public PoC status, and asset exposure. Internet-facing, privileged, or business-critical deployments should be handled first.

Are workarounds available?

The supplied mitigation guidance says to apply vendor patches and restrict external exposure until fixed. Fixed-version evidence is listed in the mitigation section above.

Which threat actors are linked publicly?

No public threat actor linkage is confirmed from current sources. Do not attribute exploitation to a threat actor unless the source evidence explicitly supports that linkage.

What should be done in the next 24 hours?

Identify exposed assets running affected vendor/product/version combinations. Treat as emergency remediation because CISA KEV status is present. Search available logs for exploit probes, errors, authentication anomalies, or suspicious child processes matching the vulnerability class. Open remediation tickets with affected assets, owners, evidence status, and detection coverage so decisions are traceable.

CISA KEVhighRace Conditionpublic exploit

CVE-2015-3246

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

Q: Is it in CISA KEV?

Yes. The supplied enrichment data lists CVE-2015-3246 in CISA KEV with 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.. KEV status should be monitored because it can change after initial disclosure or after exploitation becomes publicly confirmed.

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.

Published Aug 11, 2015Updated Aug 27, 2026Sources: NVD, Red Hat (CNA), CISA, FIRST EPSS, Exploit-DB, Red Hat (VEX), SOCRadar CTI

Triage

Is it exploited, how likely is exploitation, what does it touch, and how severe do the scoring sources call it.

Exploitation

Confirmed

CISA KEV, listed Aug 26, 2026

EPSS

ahead of 95% of scored CVEs

Affects

Red Hat

Libuser

CVSS base

7.2

high · 3 sources

Remediation

The vendor's own words where we have them.

Upgrade Libuser to a fixed release. Apply vendor patches per advisory and restrict external exposure of the affected component until patched.

CISA 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.

Federal deadline Sep 9, 2026 — in 10 days

Red Hat VEX · CVE-2015-3246

fixed125affected1not affected0

vendor_fix: Before applying this update, make sure all previously released errata relevant to your system have been applied. For details on how to apply this update, refer to: https://access.…

workaround: 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 su…

First 24 hours

Ordered from the record's own fields — exposure first, because you cannot patch what you have not found.

Identify exposed assets running affected vendor/product/version combinations.
Treat as emergency remediation because CISA KEV status is present.
Search available logs for exploit probes, errors, authentication anomalies, or suspicious child processes matching the vulnerability class.

Affected scope

Vendor, product and version as the advisories word them.

Vendor	Product	Versions	Status
Red Hat	Libuser	—	Vulnerable

Attack characteristics

The CVSS vector, decoded. It describes the attack, not your exposure to it.

Availability

Changed

Confidentiality

Changed

Integrity

Changed

Attack Complexity

Low

Attack Vector

Local

Every base score collected

Sources score independently and disagree; each row says who scored it and under which version.

Score	Version	Severity	Expl.	Impact	Source
5.1	CVSS 3.1	medium	1.4	3.6	CNA
7.2	CVSS 2.0	high	3.9	10	NVD
6.8	CVSS 3.1	medium	—	—	Red Hat (VEX)

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

Weakness & attack patterns

CWE-264
CWE-367

Attack patterns reported against this CVE. The ATT&CK techniques below are inferred from its weakness class.

CAPEC-76 · Manipulating Web Input to File System CallsCAPEC-17 · Using Malicious FilesCAPEC-69 · Target Programs with Elevated PrivilegesCAPEC-35 · Leverage Executable Code in Non-Executable FilesCAPEC-58 · Restful Privilege Elevation

CISA KEV details

CISA lists a CVE here once it has evidence of exploitation against real targets.

CISAThat month →

Listed

Aug 26, 2026

Federal deadline

Sep 9, 2026

in 10 days

Ransomware use

Unknown

CISA records ransomware use only for campaigns it has confirmed, so “Unknown” means unrecorded, not ruled out. The deadline binds US federal agencies; for everyone else it is a date to argue against.

Public exploit

Capability, not use: code existing is a different claim from anyone running it.

Repositories

1 of the 2 sampled are weaponized

Exploit entries

Exploit-DB and CTI exploit indexes

Social mentions

Posts naming this CVE. Attention, not evidence of exploitation — it spikes on disclosure and decays whether or not anything is exploited.

Detection

Read off the CVSS vector and the weakness class. Starting points, not rules we have tested.

Search application, proxy, and WAF logs for requests touching /etc/passwd.
Monitor for scanner or exploit-pattern traffic after 7 public PoC repositories were reported.

Groups associated with this CVE

Groups reported in connection with this vulnerability. A reported association, not a confirmed observation of that group using it — and not scoped to any sector or campaign.

hash37cabc04da36e710dd4aee8609ab7553c039a54dd085460854e9ddb49b0e703286
Public Malware Feeds · Aug 20, 2026
hashd190b349d791267a9583ba9f4a1ab0e4199d1a3abfd4dae514ed5def0754ba9471
Cisco Talos · Aug 20, 2026
hash8280502c2c6902e61fc4c02a9a81b4720688449a5bca3d89dbd1e2edd507c69a71
Cisco Talos · Aug 20, 2026
hash23a83c6bbdd7d6c09a5187338065d15f2a90a252772813cba83b9818aa56cef771
Cisco Talos · Aug 20, 2026
hash00892f276299a13721642e8a9bcbcb949a658547c6c8271866a1997b79f1e5c571
Cisco Talos · Aug 20, 2026

5 more indicators on this CVEShowing 5 of 10 · Hashes, addresses and domains from a live threat exchangeUnlock free

Timeline

What happened to this CVE, newest first — with the readings a source repeats on a schedule counted underneath rather than listed.

2026
Added · CVSS 3.1 7.2 (AV:L)
Aug 27, 2026 · NVD
Added to CISA KEV catalog
Aug 26, 2026 · CISA
2023
CVE is exploited. "ARPSyndicate/cvemon"
Dec 15, 2023 · SOCRadar CTI
2018
Added · Verified local entry: Libuser - 'roothelper' Local Privilege Escalation (Metasploit)
May 16, 2018 · Exploit-DB
Added · Verified local entry: Libuser - 'roothelper' Local Privilege Escalation (Metasploit)
May 16, 2018 · Exploit-DB
2015
Initial · CVE published
Aug 11, 2015 · NVD
Added · Verified dos entry: Libuser Library - Multiple Vulnerabilities
Jul 27, 2015 · Exploit-DB

Source activity

Readings a source repeats on a schedule, counted rather than listed.

2×Tweets · 1 time tweeted.Aug 27, 2026 – Aug 29, 2026 · SOCRadar CTI
2×Github ReposApr 13, 2021 – Aug 27, 2026 · SOCRadar CTI
1×CVE appeared in the Cve Trends.Aug 29, 2026 · SOCRadar CTI
1×CVE modified by NIST: CISA KEV details updated.Aug 27, 2026 · SOCRadar CTI
1×SVRS is calculatedAug 27, 2026 · SOCRadar CTI

References

21 on the record

lists.fedoraproject.org/pipermail/package-announce/2015-August/163044.html
Broken Link
lists.fedoraproject.org/pipermail/package-announce/2015-July/162947.html
Broken Link
lists.opensuse.org/opensuse-security-announce/2015-08/msg00000.html
Mailing List, Third Party Advisory, Mitre, NIST
rhn.redhat.com/errata/RHSA-2015-1482.html
Vendor Advisory, Mitre, NIST
rhn.redhat.com/errata/RHSA-2015-1483.html
Vendor Advisory, Mitre, NIST
www.securityfocus.com/bid/76022
Third Party Advisory, Mitre, NIST
www.securitytracker.com/id/1033040
Third Party Advisory, Mitre, NIST
access.redhat.com/articles/1537873
Mitigation, Vendor Advisory, NIST, MITRE_REFERENCES

Coverage

5 stories from the feeds we poll

Elsewhere on this site

Red Hatevery CVE for this vendor
August 2026what else CISA listed
Race Conditionsame class
CWE-264other pages naming this weakness

Not in any source we poll

Listed rather than left blank: an empty field and an unmeasured one look identical on screen, and only one is a reason to look elsewhere.

Only the 5 indicator(s) reported for this CVE are available; no packet-level or host-forensic artifacts supplied.
No organization-specific asset inventory, compensating-control status, or patch deployment evidence supplied.
No exploit packet captures, log samples, or incident case IDs supplied.

Answered from this record1

What should defenders know first?

CVE-2015-3246 is Red Hat Libuser Race Condition Vulnerability, a high vulnerability affecting Libuser from Red Hat. The current evidence lists it in CISA KEV, and the exploit status is: Yes: CISA KEV signal present. Public exploit evidence is: 7 public PoC repositories reported; 1 marked weaponized in current dataset. The affected-version evidence is listed in the key facts and affected products tables. Defenders should first verify whether exposed or business-critical assets run those versions, then apply vendor patches or mitigations, restrict reachable attack surface, and preserve logs for detection review. CVSS 7.2 describes technical severity, while EPSS 9% helps estimate near-term exploit likelihood; neither replaces asset context. Unknown fields should remain explicit in tickets, and threat actor, IOC, victimology, or payload claims should not be added unless a cited source supports them. Monitor CISA KEV, vendor advisories, NVD changes, public PoC repositories, and internal telemetry for update triggers.