CVE-2026-11404

high

Description

Cesanta Mongoose before 7.22 contains an out-of-bounds read in the built-in TLS server function mg_tls_server_recv_hello(), which uses an attacker-controlled session_id_len byte from a TLS ClientHello as a buffer index without validating it against the length of received data. A remote, unauthenticated attacker can send a single crafted ClientHello with an oversized session id length to read past the receive buffer, crashing any HTTPS, MQTTS, or WSS service built on MG_TLS_BUILTIN.

References

https://www.vulncheck.com/advisories/cesanta-mongoose-out-of-bounds-read-in-mg-tls-builtin-clienthello-session-id-parsing

https://github.com/cesanta/mongoose/releases/tag/7.22

https://github.com/cesanta/mongoose/commit/c288ac1f38424ffdd4d2fd5e1893fd4962642db3

https://github.com/cesanta/mongoose

Details

Source: Mitre, NVD

Published: 2026-07-09

Updated: 2026-07-09

Risk Information

CVSS v2

Base Score: 7.8

Vector: CVSS2#AV:N/AC:L/Au:N/C:N/I:N/A:C

Severity: High

CVSS v3

Base Score: 7.5

Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Severity: High

CVSS v4

Base Score: 8.7

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

Severity: High