CVE-2016-6603

CRITICALNVD 9.89.8—
EchelonGraph scoreMEDIUM confidence

Score 9.8 from GitHub Security Advisory (severity: CRITICAL) published 2022-05-14. NVD baseline CVSS 9.8; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, nvd
Elevated
9.8
EchelonGraph verdictPatch this weekExploitation is likely or a public exploit exists.
  • High exploitation likelihood — EPSS 87%
CISA-KEV: Not listedEPSS: 87%CVSS: 9.8Exploit: NoneExposed: 0

No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.

ZOHO WebNMS Framework 5.2 and 5.2 SP1 allows remote attackers to bypass authentication and impersonate arbitrary users via the UserName HTTP header.

CVSS v3
9.8
EG Score
9.8(medium)
EG Risk
83(Track*)
EG Risk 83/100SSVC: Track*

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
Severity98% × 45%
Exploitation87% × 40%
Automatability30% × 15%
Action: Watch closely — could escalate to Attend.
EPSS
99.7%
KEV
Not listed

Published

January 23, 2017

Last Modified

May 13, 2026

Advisory Details (5)

Auto-updated May 14, 2026
🔬 Proof of concept available. No patch confirmed yet.
generic🟡 PoC Available

Full Disclosure: [CVE-2016-6600/1/2/3]: Multiple vulnerabilities (RCE, file download, etc) in WebNMS Framework 5.2 / 5.2 SP1

http://seclists.org/fulldisclosure/2016/Aug/54
generic🟡 PoC Available

WebNMS Framework Server 5.2/5.2 SP1 - Multiple Vulnerabilities - JSP webapps Exploit

https://www.exploit-db.com/exploits/40229/
generic🟡 PoC Available

PoC/advisories/webnms-5.2-sp1-pwn.txt at master · pedrib/PoC · GitHub

https://github.com/pedrib/PoC/blob/master/advisories/webnms-5.2-sp1-pwn.txt
generic
http://www.securityfocus.com/bid/92402
generic
http://www.securityfocus.com/archive/1/539159/100/0/threaded

Data Freshness Timeline

(refreshed 6× in last 7d / 16× 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.

  1. 2026-07-24 14:13 UTCEPSS rescore
  2. 2026-07-23 01:23 UTCEG score recompute
  3. 2026-07-22 22:03 UTCEG score recompute
  4. 2026-07-22 14:04 UTCEPSS rescore
  5. 2026-07-19 14:28 UTCEPSS rescore
  6. 2026-07-19 14:28 UTCEPSS rescore
  7. 2026-07-15 16:54 UTCEPSS rescore
  8. 2026-07-15 16:54 UTCEPSS rescore
  9. 2026-07-13 06:09 UTCEPSS rescore
  10. 2026-07-12 05:43 UTCEPSS rescore
  11. 2026-07-12 05:43 UTCEPSS rescore
  12. 2026-07-08 15:10 UTCEPSS rescore
  13. 2026-07-04 06:28 UTCEPSS rescore
  14. 2026-06-30 23:19 UTCEPSS rescore
  15. 2026-06-30 23:19 UTCEPSS rescore
  16. 2026-06-25 13:47 UTCEPSS rescore
  17. 2026-06-23 21:30 UTCEPSS rescore
  18. 2026-06-18 17:50 UTCEPSS rescore
  19. 2026-06-18 17:50 UTCEPSS rescore
  20. 2026-06-17 17:50 UTCEPSS rescore
  21. 2026-06-17 17:50 UTCEPSS rescore
  22. 2026-06-15 17:45 UTCEPSS rescore
  23. 2026-06-14 23:14 UTCEPSS rescore
  24. 2026-06-14 23:14 UTCEPSS rescore
  25. 2026-06-13 22:57 UTCEPSS rescore
Show 34 more
  1. 2026-06-13 22:57 UTCEPSS rescore
  2. 2026-06-12 23:09 UTCEPSS rescore
  3. 2026-06-11 13:57 UTCEPSS rescore
  4. 2026-06-05 22:44 UTCEPSS rescore
  5. 2026-06-05 06:08 UTCEPSS rescore
  6. 2026-06-05 06:08 UTCEPSS rescore
  7. 2026-06-04 13:10 UTCEPSS rescore
  8. 2026-06-04 13:10 UTCEPSS rescore
  9. 2026-06-01 13:49 UTCEPSS rescore
  10. 2026-06-01 13:49 UTCEPSS rescore
  11. 2026-05-31 22:28 UTCEPSS rescore
  12. 2026-05-31 22:28 UTCEPSS rescore
  13. 2026-05-29 13:41 UTCEPSS rescore
  14. 2026-05-27 13:38 UTCEPSS rescore
  15. 2026-05-27 13:38 UTCEPSS rescore
  16. 2026-05-26 13:42 UTCEPSS rescore
  17. 2026-05-26 13:42 UTCEPSS rescore
  18. 2026-05-24 16:44 UTCEPSS rescore
  19. 2026-05-22 21:15 UTCEPSS rescore
  20. 2026-05-20 22:37 UTCEPSS rescore
  21. 2026-05-20 22:37 UTCEPSS rescore
  22. 2026-05-20 22:37 UTCEPSS rescore
  23. 2026-05-20 10:07 UTCGHSA enrichment
  24. 2026-05-20 05:48 UTCGHSA enrichment
  25. 2026-05-20 01:29 UTCGHSA enrichment
  26. 2026-05-19 21:10 UTCGHSA enrichment
  27. 2026-05-19 16:51 UTCGHSA enrichment
  28. 2026-05-19 12:32 UTCGHSA enrichment
  29. 2026-05-19 08:12 UTCGHSA enrichment
  30. 2026-05-19 03:53 UTCGHSA enrichment
  31. 2026-05-18 23:34 UTCEG score recompute
  32. 2026-05-18 21:30 UTCEPSS rescore
  33. 2026-05-18 21:30 UTCEPSS rescore
  34. 2026-05-18 21:30 UTCEPSS rescore

Publicly available exploits

(1 reference)

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

  • Exploit-DBEDB-40229
    First seen Aug 10, 2016

    WebNMS Framework Server 5.2/5.2 SP1 - Multiple Vulnerabilities

    Open source ↗

Frequently asked(5)

What is CVE-2016-6603?
CVE-2016-6603 is a critical vulnerability published on January 23, 2017. ZOHO WebNMS Framework 5.2 and 5.2 SP1 allows remote attackers to bypass authentication and impersonate arbitrary users via the UserName HTTP header.
When was CVE-2016-6603 disclosed?
CVE-2016-6603 was first published in the National Vulnerability Database on January 23, 2017, with the most recent update on May 13, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2016-6603 actively exploited?
CVE-2016-6603 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 99.7% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.
What is the CVSS score of CVE-2016-6603?
CVE-2016-6603 has a CVSS v3 base score of 9.8 (NVD).
How do I remediate CVE-2016-6603?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2016-6603, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

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