CVE-2026-6985mediumCWE-404CWE-835

CVE-2026-6985: medium-severity vulnerability in Cesanta Mongoose

Cesanta Mongoose TCP Option net_builtin.c handle_opt infinite loop

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33Vexday Risk Score

No sign of exploitation. It has a public proof of concept.

ssvc Attendcvss 6.9epss 0.6%
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: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
Affected products
Cesanta · Mongoose
⚠ Public resources, to assess the exposure of systems you control or are authorized to test. Test only with authorization.
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