PT-2026-56811 · Cesanta · Mongoose

Shukhratbek Uraiimov · Published 2026-07-09 · Updated 2026-07-09 · CVE-2026-11404

Mitre

CVSS v3.1

7.5

High

Base vector

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

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.

Fix

Out of bounds Read

Weakness Enumeration

CWE-125

Related Identifiers

CVE-2026-11404

Affected Products

Mongoose

References · 5

• https://github.com/cesanta/mongoose/commit/c288ac1f38424ffdd4d2fd5e1893fd4962642db3 · Patch
• https://github.com/cesanta/mongoose/releases/tag/7.22 · Patch
• https://nvd.nist.gov/vuln/detail/CVE-2026-11404 · Security Note
• https://github.com/cesanta/mongoose · Note
• https://vulncheck.com/advisories/cesanta-mongoose-out-of-bounds-read-in-mg-tls-builtin-clienthello-session-id-parsing · Note