CVE-2026-6985CWE-404CWE-835

Cesanta Mongoose TCP Option net_builtin.c handle_opt infinite loop

Medium · published April 25, 2026

CVSS v4.0
6.9
EPSS
1%
Percentile
60.0
In the wild
Unconfirmed
What it is

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.

The record
Technical detail
CVSS v4.0
6.9 · MEDIUM
Vector
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
EPSS
0.00923 · 60.0th percentile
Weaknesses
CWE-404 · Improper Resource Shutdown or Release; CWE-835 · Loop with Unreachable Exit Condition ('Infinite Loop')
Published
2026-04-25T16:15Z
EPSS history
Timeline
  • 25 APR 16:15Z
    Cesanta Mongoose TCP Option net_builtin.c handle_opt infinite loop
    cvelistv5