CVE-2015-3246
HighExploitedPublic exploitlibuser 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.
Published Aug 11, 2015 · Updated Oct 2, 2026 · Also known as DEBIAN-CVE-2015-3246, UBUNTU-CVE-2015-3246
Key Facts
Patch immediately- CVE-2015-3246 is a high-severity vulnerability (CVSS 7.4 v3.1) affecting Libuser (Libuser Project), Opensuse, Enterprise Linux (Redhat) and 9 more products.
- It is exploited in the wild, listed in CISA KEV, Industry KEV feed, CIRCL KEV, ENISA EUVD since Aug 20, 2026. Public exploit code is available.
- EPSS estimates a 8.5% probability of exploitation in the next 30 days.
- Fixed versions are available, including Libuser 0:0.56.13-8.el6_7, Libuser 0:0.60-7.ael7b_1, Libuser 0.56.13-8.15.amzn1.
- Brandefense priority: patch immediately, because it is listed as exploited in the wild.
CVSS v3.1
7.4
CVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
EPSS (30-day exploit likelihood)
8.5%
Higher than 94.9% of all scored CVEs
Exploited in the wild
Yes
4 catalog listings
Public exploit code
Available
Proof-of-concept or weaponized module
Get the full CVE-2015-3246 brief as a PDF
Every affected product and fixed release, exploitation status and a first 24 hours response checklist, emailed within minutes.
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.
Known-Exploited Catalog Listings
| Catalog | Added | Remediation due | Ransomware use |
|---|---|---|---|
| CISA KEV | Aug 26, 2026 | Sep 9, 2026 | Not reported |
| Industry KEV feed | Aug 20, 2026 | Sep 9, 2026 | Not reported |
| CIRCL KEV | Aug 26, 2026 | Sep 9, 2026 | Not reported |
| ENISA EUVD | Aug 26, 2026 | n/a | Not reported |
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.
Affected Products
48 affected entries in total| Product | Affected versions | Fixed in |
|---|---|---|
| LibuserLibuser Project | 0.60-1, 0.60-2, 0.60-3, 0.60-4, 0.60-5, 0.60-6 | 0.56.13-8 |
| OpensuseOpensuse | 13.2 | n/a |
| Enterprise LinuxRedhat | 5.0, 6.0, 7.0 | n/a |
| libuser-develamazon | See advisory | 0.56.13-8.15.amzn1 |
| libuser-pythonamazon | See advisory | 0.56.13-8.15.amzn1 |
Patched Releases
Libuser
0:0.56.13-8.el6_7, 0:0.60-7.ael7b_1, 0.56.13-8.15.amzn1, 0.56.13-8.el6_7, 0.60-3.3.1, 0.60-7.el7_1, 1:0.56.9.dfsg.1-1.2+deb7u1, 1:0.56.9.dfsg.1-1.2ubuntu2+esm1, 1:0.62~dfsg-0.1, 0.56.13-8, 0.60-7, 0.56.13-5
libuser-debuginfo
0.60-3.3.1
libuser-debugsource
0.60-3.3.1
libuser-devel
0.56.13-8.15.amzn1, 0.56.13-8.el6_7, 0.60-3.3.1, 0.60-7.el7_1
libuser-lang
0.60-3.3.1
libuser-python
0.56.13-8.15.amzn1, 0.56.13-8.el6_7, 0.60-3.3.1, 0.60-7.el7_1
libuser-python-debuginfo
0.60-3.3.1
libuser1
0.60-3.3.1
libuser1-debuginfo
0.60-3.3.1
usermode
1.102-3.18.amzn1
Timeline
Publicly disclosed
Aug 11, 2015
Added to Industry KEV feed
Aug 20, 2026
Added to CISA KEV
Aug 26, 2026
Added to CIRCL KEV
Aug 26, 2026
Added to ENISA EUVD
Aug 26, 2026
Last updated
Oct 2, 2026
Weakness Type
- CWE-264
- CWE-367 Time-of-check Time-of-use (TOCTOU) Race Condition
References
- advisoryRHSA-2015:1482
- advisoryRHSA-2015:1483
- advisoryhttps://security-tracker.debian.org/tracker/CVE-2015-3246
- advisoryhttps://ubuntu.com/security/CVE-2015-3246
- advisoryhttps://www.cisa.gov/known-exploited-vulnerabilities-catalog
FAQ
Common Questions.
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.
Affected: Libuser (Libuser Project) versions 0.60-1, 0.60-2, 0.60-3, 0.60-4, 0.60-5, 0.60-6; Opensuse versions 13.2; Enterprise Linux (Redhat) versions 5.0, 6.0, 7.0, among others. The full list is in the CVE brief.
It is exploited in the wild, listed in CISA KEV, Industry KEV feed, CIRCL KEV, ENISA EUVD since Aug 20, 2026.
Yes. It was added on Aug 26, 2026 with a federal remediation due date of Sep 9, 2026.
Public exploit code is available.
Fixed versions are available, including Libuser 0:0.56.13-8.el6_7, Libuser 0:0.60-7.ael7b_1, Libuser 0.56.13-8.15.amzn1.
Brandefense priority: patch immediately, because it is listed as exploited in the wild.
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