CVE-2026-6985

A weakness has been identified in Cesanta Mongoose up to 7.20. This vulnerability affects the function handle_opt of the file /src/net_builtin.c of the component TCP Option Handler. This manipulation of the argument optlen causes infinite loop. The attack is possible to be carried out remotely. The exploit has been made available to the public and could be used for attacks. Upgrading to version 7.21 is able to resolve this issue. Upgrading the affected component is advised. VulDB has contacted the vendor early and they confirmed quickly, that this issue got fixed already.

CVSS v3 5.3 MEDIUM
CVSS v2.0 5.0 MEDIUM

5.3^/10

CVSS v3 : MEDIUM

Vector :

Exploitability : 3.9 / Impact : 1.4

Attack Vector NETWORK

Attack Complexity LOW

Privileges Required NONE

User Interaction NONE

Confidentiality Impact NONE

Integrity Impact NONE

Availability Impact LOW

Scope UNCHANGED

5.0^/10

CVSS v2.0 : MEDIUM

Vector : AV:N/AC:L/Au:N/C:N/I:N/A:P

Exploitability : 10.0 / Impact : 2.9

Access Vector NETWORK

Access Complexity LOW

Authentication NONE

Confidentiality Impact NONE

Integrity Impact NONE

Availability Impact PARTIAL

References

Link	Resource
https://github.com/cesanta/mongoose/releases/tag/7.21	Product Release Notes
https://github.com/dwBruijn/CVEs/blob/main/Mongoose/TCP_opt_dos.md	Exploit Third Party Advisory
https://vuldb.com/submit/796230	Third Party Advisory VDB Entry
https://vuldb.com/vuln/359528	Third Party Advisory VDB Entry
https://vuldb.com/vuln/359528/cti	Permissions Required VDB Entry

Configurations

Configuration 1 (hide)

cpe:2.3:a:cesanta:mongoose:*:*:*:*:*:*:*:*

History

No history.

Information

Published : 2026-04-25 17:16

Updated : 2026-06-17 11:01

NVD link : CVE-2026-6985

Mitre link : CVE-2026-6985

CVE.ORG link : CVE-2026-6985

JSON object : View

Products Affected

cesanta

mongoose

CWE

CWE-404

Improper Resource Shutdown or Release

CWE-835

Loop with Unreachable Exit Condition ('Infinite Loop')

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