CVE-2026-6985: Cesanta Mongoose TCP Option net_builtin.c handle_opt infinite loop
A weakness has been identified in Cesanta Mongoose up to 7.20. This vulnerability affects the function handleopt of the file /src/netbuiltin.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.
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Upgrade
Upgrade
Cesanta Mongooseto a version that resolves this vulnerability.Fixed in 7.21
Event History
Frequently Asked Questions
What is the severity of CVE-2026-6985?
CVE-2026-6985 has been classified as a high severity vulnerability due to the potential for an infinite loop affecting the TCP Option Handler.
How do I fix CVE-2026-6985?
To mitigate CVE-2026-6985, upgrade Cesanta Mongoose to version 7.21 or later, which addresses the identified infinite loop issue.
What software is affected by CVE-2026-6985?
CVE-2026-6985 affects Cesanta Mongoose versions up to and including 7.20.
What is the attack vector for CVE-2026-6985?
The attack vector for CVE-2026-6985 involves manipulating the argument optlen within the function handle_opt in the TCP Option Handler.
What potential impact does CVE-2026-6985 have on my system?
Exploitation of CVE-2026-6985 can lead to denial of service conditions due to an infinite loop affecting system performance.