Which products and versions are affected by CVE-2016-6603?

Affected: Webnms Framework (Zohocorp) versions 5.2, 5.2-sp1. The full list is in the CVE brief.

Is CVE-2016-6603 being exploited in the wild?

It is not listed in any known-exploited vulnerabilities catalog.

Is CVE-2016-6603 in the CISA KEV catalog?

No, it is not currently listed in the CISA Known Exploited Vulnerabilities catalog.

Is there a public exploit for CVE-2016-6603?

Public exploit code is available.

Is there a fix for CVE-2016-6603?

No fixed version is listed yet; check the vendor advisory for mitigations.

How urgently should CVE-2016-6603 be patched?

Brandefense priority: patch immediately, because it is very likely to be exploited soon.

Request A Demo

Vulnerability Intelligence

CVE-2016-6603

CriticalPublic exploit

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

Published Jan 23, 2017 · Updated May 12, 2026

Key Facts

Patch immediately

CVE-2016-6603 is a critical-severity vulnerability (CVSS 9.8 v3) affecting Webnms Framework (Zohocorp).
It is not listed in any known-exploited vulnerabilities catalog. Public exploit code is available.
EPSS estimates a 87% probability of exploitation in the next 30 days.
No fixed version is listed yet; check the vendor advisory for mitigations.
Brandefense priority: patch immediately, because it is very likely to be exploited soon.

CVSS v3

9.8

CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

EPSS (30-day exploit likelihood)

87%

Higher than 99.7% 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-2016-6603 brief as a PDF

Every affected product and fixed release, exploitation status and a first 24 hours response checklist, emailed within minutes.

Description

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

Affected Products

2 affected entries in total

Product	Affected versions	Fixed in
Webnms FrameworkZohocorp	5.2, 5.2-sp1	n/a

Timeline

Publicly disclosed
Jan 23, 2017
Last updated
May 12, 2026

Weakness Type

CWE-20 Improper Input Validation

References

4 more references in the full CVE brief

FAQ

Common Questions.

ZOHO WebNMS Framework 5.2 and 5.2 SP1 allows remote attackers to bypass authentication and impersonate arbitrary users via the UserName HTTP header.
Affected: Webnms Framework (Zohocorp) versions 5.2, 5.2-sp1. 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.
No fixed version is listed yet; check the vendor advisory for mitigations.
Brandefense priority: patch immediately, because it is very likely to be exploited soon.

Is CVE-2016-6603 Running On Your Attack Surface?

Brandefense maps vulnerabilities like this one to your internet-facing assets and tells you exactly where to patch.