CVE-2026-11404 — HIGH (7.5)

Vulnerability 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.

CVSS Score

7.5

HIGH

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

Attack Vector

NETWORK

Attack Complexity

LOW

Privileges Required

NONE

User Interaction

NONE

Scope

UNCHANGED

Confidentiality

NONE

Integrity

NONE

Availability

HIGH

Related Weaknesses (CWE)

CWE-125

References

FAQ

What is CVE-2026-11404?

CVE-2026-11404 is a vulnerability with a CVSS score of 7.5 (HIGH). 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...

How severe is CVE-2026-11404?

CVE-2026-11404 has been rated HIGH with a CVSS base score of 7.5/10. Review the CVSS metrics above for detailed severity breakdown.

Is there a patch for CVE-2026-11404?

Check the references section above for vendor advisories and patch information. Review vendor security bulletins for remediation guidance.