CVE-2016-2056

HIGHNVD 8.88.9▲
EchelonGraph scoreHIGH confidence

Score elevated to 8.9 because EPSS predicts 55% probability of exploitation within the next 30 days (98th percentile of EPSS-scored CVEs). NVD baseline CVSS 8.8 retained for reference. Confidence: see factors.

Triggered by: EPSS exploit prediction ≥85%
Sources: epss, ghsa, nvd
Weaponized
8.9EG
EchelonGraph verdictPatch this weekExploitation is likely or a public exploit exists.
  • High exploitation likelihood — EPSS 55%
  • Public exploit code is available (Metasploit, Exploit-DB (verified), epss top5pct, epss high, public exploit)
CISA-KEV: Not listedEPSS PROB: 55%CVSS: 8.8Exploit: Metasploit · Exploit-DB (verified) · epss top5pct · epss high · public exploitExposed services: Not assessed

A fix is available — apply it.

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.

CVSS v3
8.8
EG Score
8.9HIGHhigh confidence
EG Risk
71
EG Risk 71/100CISA SSVC

EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).

How it’s computed
Severity89% × 45%
Exploitation65% × 40%
Automatability30% × 15%
CISA SSVC: Track at low or medium mission impact; Track* or Attend at high (mission-essential systems).
Action: A fix is available. Apply it within your standard update timelines at low or medium mission impact and sooner than that at high.
EPSS PROB
55%
EPSS %ILE
98th
KEV
Not listed

CISA SSVCTrack at low or medium mission impact; Track* or Attend at high (mission-essential systems).

A fix is available. Apply it within your standard update timelines at low or medium mission impact and sooner than that at high.

Exploitation public PoC (EG-KEV: weaponized) · Automatable unknown (not published for this CVE) · Technical impact partial (CVSS below 9.0). Mission impact is CISA's Mission & Well-being decision point, and only you can judge it: high means the affected system is essential to your organisation's mission, or its compromise could cause irreversible harm to people. CISA's decision table

Published

April 13, 2016

Last Modified

June 17, 2026

Advisory Details (4)

Auto-updated May 22, 2026
Patch available.
generic

Xymon Systems and Network Monitor / Code / Commit [r7892]

https://sourceforge.net/p/xymon/code/7892/
generic
http://www.securityfocus.com/archive/1/537522/100/0/threaded
generic

[SECURITY] [DSA 3495-1] xymon security update

http://www.debian.org/security/2016/dsa-3495
generic

Packet Storm

http://packetstormsecurity.com/files/153620/Xymon-useradm-Command-Execution.html

Affected Packages

(6 across 6 ecosystems)
Debian:11(1)
PackageVulnerable rangeFix by version rangeDependents
xymon—
  • every version up to 4.3.25-1: fixed in 4.3.25-1
—
Debian:12(1)
PackageVulnerable rangeFix by version rangeDependents
xymon—
  • every version up to 4.3.25-1: fixed in 4.3.25-1
—
Debian:13(1)
PackageVulnerable rangeFix by version rangeDependents
xymon—
  • every version up to 4.3.25-1: fixed in 4.3.25-1
—
Debian:14(1)
PackageVulnerable rangeFix by version rangeDependents
xymon—
  • every version up to 4.3.25-1: fixed in 4.3.25-1
—
Debian:7(1)
PackageVulnerable rangeFix by version rangeDependents
xymon4.3.0~beta2.dfsg-9.1
  • every version up to 4.3.0~beta2.dfsg-9.1+deb7u1: fixed in 4.3.0~beta2.dfsg-9.1+deb7u1
—
Debian:8(1)
PackageVulnerable rangeFix by version rangeDependents
xymon4.3.17-6
  • every version up to 4.3.17-6+deb8u1: fixed in 4.3.17-6+deb8u1
—

Weakness Classification(1)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Data Freshness Timeline

(refreshed 5× in last 7d / 18× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

Showing the most recent 100 of 123 total refreshes for this CVE.

  1. 2026-10-05 17:38 UTCEPSS rescore
  2. 2026-10-03 14:21 UTCEPSS rescore
  3. 2026-10-01 19:43 UTCEPSS rescore
  4. 2026-09-30 14:58 UTCEPSS rescore
  5. 2026-09-30 09:12 UTCEG score recompute
  6. 2026-09-27 13:40 UTCEPSS rescore
  7. 2026-09-26 15:53 UTCEPSS rescore
  8. 2026-09-26 15:53 UTCEPSS rescore
  9. 2026-09-24 13:59 UTCEPSS rescore
  10. 2026-09-23 13:41 UTCEPSS rescore
  11. 2026-09-19 01:30 UTCOSV refresh
  12. 2026-09-18 19:22 UTCEPSS rescore
  13. 2026-09-17 19:21 UTCEPSS rescore
  14. 2026-09-15 03:05 UTCEPSS rescore
  15. 2026-09-13 16:41 UTCEPSS rescore
  16. 2026-09-12 14:55 UTCEPSS rescore
  17. 2026-09-10 09:26 UTCEPSS rescore
  18. 2026-09-07 15:56 UTCEPSS rescore
  19. 2026-09-04 13:56 UTCEPSS rescore
  20. 2026-09-02 14:07 UTCEPSS rescore
  21. 2026-09-01 03:31 UTCEPSS rescore
  22. 2026-08-31 05:04 UTCOSV refresh
  23. 2026-08-30 19:12 UTCEPSS rescore
  24. 2026-08-26 14:41 UTCEPSS rescore
  25. 2026-08-21 23:44 UTCEPSS rescore
Show 75 more
  1. 2026-08-19 16:59 UTCEPSS rescore
  2. 2026-08-18 13:43 UTCEPSS rescore
  3. 2026-08-17 13:42 UTCEPSS rescore
  4. 2026-08-16 14:51 UTCEPSS rescore
  5. 2026-08-16 02:09 UTCEPSS rescore
  6. 2026-08-15 01:25 UTCEPSS rescore
  7. 2026-08-14 12:54 UTCOSV refresh
  8. 2026-08-12 13:46 UTCEPSS rescore
  9. 2026-08-11 13:36 UTCEPSS rescore
  10. 2026-08-08 16:32 UTCEPSS rescore
  11. 2026-08-06 13:42 UTCEPSS rescore
  12. 2026-08-04 15:04 UTCEPSS rescore
  13. 2026-08-04 10:32 UTCEPSS rescore
  14. 2026-07-30 16:23 UTCEPSS rescore
  15. 2026-07-30 01:26 UTCEPSS rescore
  16. 2026-07-30 01:24 UTCOSV refresh
  17. 2026-07-28 15:31 UTCEPSS rescore
  18. 2026-07-26 14:50 UTCEPSS rescore
  19. 2026-07-25 14:13 UTCEPSS rescore
  20. 2026-07-23 14:14 UTCEPSS rescore
  21. 2026-07-23 01:22 UTCEG score recompute▲ 0.10
  22. 2026-07-22 22:01 UTCEG score recompute
  23. 2026-07-22 14:04 UTCEPSS rescore
  24. 2026-07-21 15:21 UTCEPSS rescore
  25. 2026-07-21 15:21 UTCEPSS rescore
  26. 2026-07-20 17:03 UTCEPSS rescore
  27. 2026-07-19 02:26 UTCEPSS rescore
  28. 2026-07-19 02:26 UTCEPSS rescore
  29. 2026-07-18 10:00 UTCEPSS rescore
  30. 2026-07-18 10:00 UTCEPSS rescore
  31. 2026-07-16 16:59 UTCEPSS rescore
  32. 2026-07-16 16:59 UTCEPSS rescore
  33. 2026-07-15 16:54 UTCEPSS rescore
  34. 2026-07-15 16:54 UTCEPSS rescore
  35. 2026-07-15 01:56 UTCEPSS rescore
  36. 2026-07-15 01:56 UTCEPSS rescore
  37. 2026-07-13 22:26 UTCEPSS rescore
  38. 2026-07-13 06:09 UTCEPSS rescore
  39. 2026-07-12 10:38 UTCOSV refresh
  40. 2026-07-12 05:43 UTCEPSS rescore
  41. 2026-07-12 05:43 UTCEPSS rescore
  42. 2026-07-11 08:23 UTCEPSS rescore
  43. 2026-07-09 19:05 UTCEPSS rescore
  44. 2026-07-06 16:24 UTCEPSS rescore
  45. 2026-07-06 16:24 UTCEPSS rescore
  46. 2026-07-05 02:27 UTCEPSS rescore
  47. 2026-07-01 15:02 UTCEPSS rescore
  48. 2026-06-28 14:04 UTCEPSS rescore
  49. 2026-06-28 04:53 UTCEPSS rescore
  50. 2026-06-27 03:05 UTCEPSS rescore
  51. 2026-06-27 03:05 UTCEPSS rescore
  52. 2026-06-25 13:47 UTCEPSS rescore
  53. 2026-06-25 13:47 UTCEPSS rescore
  54. 2026-06-24 14:02 UTCEPSS rescore
  55. 2026-06-24 14:02 UTCEPSS rescore
  56. 2026-06-23 21:30 UTCEPSS rescore
  57. 2026-06-23 16:20 UTCOSV refresh
  58. 2026-06-21 01:57 UTCEPSS rescore
  59. 2026-06-21 01:57 UTCEPSS rescore
  60. 2026-06-17 17:50 UTCEPSS rescore
  61. 2026-06-17 17:50 UTCEPSS rescore
  62. 2026-06-16 17:50 UTCEPSS rescore
  63. 2026-06-16 17:50 UTCEPSS rescore
  64. 2026-06-15 17:45 UTCEPSS rescore
  65. 2026-06-14 23:14 UTCEPSS rescore
  66. 2026-06-12 23:09 UTCEPSS rescore
  67. 2026-06-12 23:09 UTCEPSS rescore
  68. 2026-06-10 22:15 UTCEPSS rescore
  69. 2026-06-06 21:29 UTCOSV refresh
  70. 2026-06-05 22:44 UTCEPSS rescore
  71. 2026-06-05 06:08 UTCEPSS rescore
  72. 2026-06-05 06:08 UTCEPSS rescore
  73. 2026-06-04 13:10 UTCEPSS rescore
  74. 2026-06-04 13:10 UTCEPSS rescore
  75. 2026-06-02 20:10 UTCEPSS rescore

Publicly available exploits

(2 references)

Working exploit code is in the public domain (1 Metasploit module) (1 Exploit-DB entry). Defenders should treat patch urgency accordingly — public PoCs typically lead to mass-exploitation within 24-72 hours.

  • Exploit-DBEDB-47114✓ verified
    First seen Jul 12, 2019

    Xymon 4.3.25 - useradm Command Execution (Metasploit)

    Open source ↗
  • Metasploitexploit/unix/webapp/xymon_useradm_cmd_exec✓ verified
    First seen Feb 14, 2016

    Xymon useradm Command Execution

    Open source ↗

Related CVEs(same product + same CWE)

Frequently asked(5)

What is CVE-2016-2056?
CVE-2016-2056 is a high vulnerability published on April 13, 2016. 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.
When was CVE-2016-2056 disclosed?
CVE-2016-2056 was first published on April 13, 2016, with the most recent update on June 17, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2016-2056 actively exploited?
CVE-2016-2056 is not currently on CISA's Known Exploited Vulnerabilities catalog. EchelonGraph's EG-KEV model classifies it as weaponized: a functional public exploit exists. FIRST EPSS estimates a 55% probability of exploitation in the next 30 days (98th percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2016-2056?
CVE-2016-2056 has a CVSS v3 base score of 8.8 (NVD). EchelonGraph synthesises NVD + CISA KEV + FIRST EPSS + GHSA into a combined EG score of 8.9 (HIGH).
How do I remediate CVE-2016-2056?
A fix for CVE-2016-2056 is available: update to the fixed version the vendor names in its advisory.

Dependency Blast Radius

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