Remote Denial of Service in Cesanta Mongoose TCP Option Handler
CVE-2026-6985

6.9MEDIUM

Key Information:

Vendor

Cesanta

Status
Mongoose
Vendor
CVE Published:
25 April 2026

Badges

👾 Exploit Exists🟡 Public PoC

What is CVE-2026-6985?

A vulnerability has been identified in Cesanta Mongoose versions up to 7.20 that allows for remote denial of service attacks. This issue arises within the TCP Option Handler's handle_opt function in the /src/net_builtin.c file, where improper manipulation of the optlen argument can lead to an infinite loop. Attackers may exploit this weakness remotely, risking system availability. It is highly recommended to upgrade to version 7.21 or later to mitigate this issue, which has already been addressed by Cesanta.

Affected Version(s)

Mongoose 7.0

Mongoose 7.1

Mongoose 7.2

Exploit Proof of Concept (PoC)

PoC code is written by security researchers to demonstrate the vulnerability can be exploited. PoC code is also a key component for weaponization which could lead to ransomware.

CVE-2026-6985 - Proof of Concept

References

https://vuldb.com/vuln/359528
vdb-entrytechnical-description
https://vuldb.com/vuln/359528/cti
signaturepermissions-required
https://vuldb.com/submit/796230
third-party-advisory

CVSS V4

Score:
6.9
Severity:
MEDIUM
Confidentiality:
None
Integrity:
None
Availability:
Low
Attack Vector:
Network
Attack Complexity:
Low
Attack Required:
None
Privileges Required:
Undefined
User Interaction:
None

Timeline

  • 🟡

    Public PoC available

  • 👾

    Exploit known to exist

  • Vulnerability published

  • Vulnerability Reserved

Credit

dwbruijn (VulDB User)
VulDB CNA Team
.