Cesanta Mongoose TCP Option net_builtin.c handle_opt infinite loop_CVE-2026-6985

6.9 / 10

MEDIUM

CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/E:P

Description

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.

Basic Information

ID CVE-2026-6985

Source VulDB

Published Apr 25, 2026 at 16:15

Affected Product

Vendor Cesanta

Product Mongoose

Version 7.0

Affected Versions Cesanta Mongoose 7.0
Cesanta Mongoose 7.1
Cesanta Mongoose 7.2
Cesanta Mongoose 7.3
Cesanta Mongoose 7.4
Cesanta Mongoose 7.5
Cesanta Mongoose 7.6
Cesanta Mongoose 7.7
Cesanta Mongoose 7.8
Cesanta Mongoose 7.9
Cesanta Mongoose 7.10
Cesanta Mongoose 7.11
Cesanta Mongoose 7.12
Cesanta Mongoose 7.13
Cesanta Mongoose 7.14
Cesanta Mongoose 7.15
Cesanta Mongoose 7.16
Cesanta Mongoose 7.17
Cesanta Mongoose 7.18
Cesanta Mongoose 7.19
Cesanta Mongoose 7.20

CWE Classification

CWE-835 CWE-404

References

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    "lastseen": "",
    "description": "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.",
    "published": "2026-04-25T16:15:13.639Z",
    "modified": "2026-04-25T16:15:13.639Z",
    "type": "cve",
    "title": "Cesanta Mongoose TCP Option net_builtin.c handle_opt infinite loop",
    "source": "VulDB",
    "references": "https://vuldb.com/vuln/359528\nhttps://vuldb.com/vuln/359528/cti\nhttps://vuldb.com/submit/796230\nhttps://github.com/dwBruijn/CVEs/blob/main/Mongoose/TCP_opt_dos.md\nhttps://github.com/cesanta/mongoose/releases/tag/7.21",
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