CVE-2016-2056
HighPublic exploitxymond in Xymon 4.1.x, 4.2.x, and 4.3.x before 4.3.25 allow remote authenticated users to execute arbitrary commands via shell metacharacters in the adduser_name argument in (1) web/useradm.c or (2) web/chpasswd.c.
Published Apr 13, 2016 · Updated Aug 4, 2026 · Also known as DEBIAN-CVE-2016-2056, UBUNTU-CVE-2016-2056
Key Facts
Patch immediately- CVE-2016-2056 is a high-severity vulnerability (CVSS 8.8 v3) affecting Xymon, Debian Linux.
- It is not listed in any known-exploited vulnerabilities catalog. Public exploit code is available.
- EPSS estimates a 55% probability of exploitation in the next 30 days.
- Fixed versions are available, including Xymon 4.3.0~beta2.dfsg-9.1+deb7u1, Xymon 4.3.17-6+deb8u1, Xymon 4.3.25-1.
- Brandefense priority: patch immediately, because it is very likely to be exploited soon.
CVSS v3
8.8
CVSS:3.0/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
EPSS (30-day exploit likelihood)
55%
Higher than 99.0% of all scored CVEs
Exploited in the wild
No known
Not in a known-exploited catalog
Public exploit code
Available
Proof-of-concept or weaponized module
Get the full CVE-2016-2056 brief as a PDF
Every affected product and fixed release, exploitation status and a first 24 hours response checklist, emailed within minutes.
Description
xymond in Xymon 4.1.x, 4.2.x, and 4.3.x before 4.3.25 allow remote authenticated users to execute arbitrary commands via shell metacharacters in the adduser_name argument in (1) web/useradm.c or (2) web/chpasswd.c.
Affected Products
55 affected entries in total| Product | Affected versions | Fixed in |
|---|---|---|
| XymonXymon | 4.1.0, 4.1.1, 4.1.2, 4.1.2-p1, 4.1.2-p2, 4.2.0, 4.2.2, 4.2.2-rc1 | 4.3.25-1 |
| Debian LinuxDebian | 8.0 | n/a |
Patched Releases
Xymon
4.3.0~beta2.dfsg-9.1+deb7u1, 4.3.17-6+deb8u1, 4.3.25-1
Timeline
Publicly disclosed
Apr 13, 2016
Last updated
Aug 4, 2026
Weakness Type
- CWE-77 Improper Neutralization of Special Elements used in a Command ('Command Injection')
References
- advisoryhttp://lists.xymon.com/pipermail/xymon/2016-February/042986.html
- advisoryhttps://security-tracker.debian.org/tracker/CVE-2016-2056
- advisoryhttps://ubuntu.com/security/CVE-2016-2056
- advisoryhttps://www.cve.org/CVERecord?id=CVE-2016-2056
- patchhttps://sourceforge.net/p/xymon/code/7892/
FAQ
Common Questions.
xymond in Xymon 4.1.x, 4.2.x, and 4.3.x before 4.3.25 allow remote authenticated users to execute arbitrary commands via shell metacharacters in the adduser_name argument in (1) web/useradm.c or (2) web/chpasswd.c.
Affected: Xymon versions 4.1.0, 4.1.1, 4.1.2, 4.1.2-p1, 4.1.2-p2, 4.2.0, 4.2.2, 4.2.2-rc1; Debian Linux versions 8.0. The full list is in the CVE brief.
It is not listed in any known-exploited vulnerabilities catalog.
No, it is not currently listed in the CISA Known Exploited Vulnerabilities catalog.
Public exploit code is available.
Fixed versions are available, including Xymon 4.3.0~beta2.dfsg-9.1+deb7u1, Xymon 4.3.17-6+deb8u1, Xymon 4.3.25-1.
Brandefense priority: patch immediately, because it is very likely to be exploited soon.
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