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CVE-2016-6603

83
FAUCET Score

CVE-2016-6603 describes a critical authentication bypass vulnerability in ZOHO WebNMS Framework versions 5.2 and 5.2 SP1, allowing remote attackers to impersonate any user by manipulating the UserName HTTP header. With a CVSS score of 9.8 (Critical), this vulnerability is easily exploitable over the network with low attack complexity, leading to complete compromise of confidentiality, integrity, and availability. While not listed on the CISA KEV catalog, exploit code is publicly available on ExploitDB, though there is no evidence of active exploitation, Metasploit modules, or significant community discussion.

Impacted Technologies

VendorProductVersion(s)CPE
5.2CPE matchmatch criteria
cpe:2.3:a:zohocorp:webnms_framework:5.2:*:*:*:*:*:*:*
5.2CPE matchmatch criteria
cpe:2.3:a:zohocorp:webnms_framework:5.2:sp1:*:*:*:*:*:*

CVSS Data

CVSS version used by this source: 3.0

9.8CRITICAL

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

Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality Impact
HIGH
Integrity Impact
HIGH
Availability Impact
HIGH
Exploitability Score
3.9
Impact Score
5.9
CvssVersion
3.0

Exploit Intelligence

EPSS Score
87.04%
Probability of exploitation in next 30 days
EPSS Percentile
99.7%
Percentile rank of EPSS score among Peer Group
As of 2026-07-26
Model: v2026.06.15
ExploitDB: EDB-40229 · Aug 10, 2016
This CVE's current EPSS score of 0.8704 is in the 99th percentile among its peer group of 36,835 CVEs.

Social Chatter

The average CVE in this peer group has 0.0 Twitter, 0.1 Reddit, 0.3 Bluesky, 0.3 Mastodon, and 2.4 GitHub mentions.

Media Mentions

No media coverage found for this CVE.

The average CVE in this peer group has 0.3 InfoSec Media, 0.0 Vendor Blog, and 0.0 Security Researcher mentions.

Remediation

Remediation records are not available for this CVE.

References

packetstormsecurity.com / files/138244/WebNMS-Framework-5.2-SP1-Traversal-Weak-Obfuscation-User-Impersonation.html
ExploitThird Party AdvisoryVDB Entry
blogs.securiteam.com / index.php/archives/2712
ExploitTechnical DescriptionThird Party Advisory
seclists.org / fulldisclosure/2016/Aug/54
ExploitMailing ListThird Party Advisory
forums.webnms.com / topic/recent-vulnerabilities-in-webnms-and-how-to-protect-the-server-against-them
github.com / pedrib/PoC/blob/master/advisories/webnms-5.2-sp1-pwn.txt
ExploitThird Party Advisory
exploit-db.com / exploits/40229
ExploitThird Party AdvisoryVDB Entry
securityfocus.com / archive/1/539159/100/0/threaded
securityfocus.com / bid/92402
Third Party AdvisoryVDB Entry