CVE-2026-11404
highpriority · track · 0EPSS 0.006 · 49 %ileEUEPSS · scored 2026-10-28
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
Technical severity, 0–10. One row per scoring source.
base score 0–10 · higher = more severe · hover a vector to decode⚠ sources disagree · medium–high · 6.6–8.7
ssvc
A stakeholder decision — act, attend, or track — from exploitation and impact.
weaknesses
The CWE weakness classes this flaw belongs to.
affected products (1)
Products and version ranges known to be affected.
also known as (3)
Other names and identifiers for this entity.
sources
Which sources assert this record, and when.
references (9)
External citations — patches, advisories, analysis.
- https://github.com/cesanta/mongoosecnnvd
- https://github.com/cesanta/mongoose/commit/c288ac1f38424ffdd4d2fd5e1893fd4962642db3cnnvd
- https://github.com/cesanta/mongoose/releases/Patchcnnvd
- https://github.com/cesanta/mongoose/releases/tag/7.22cnnvd
- https://www.vulncheck.com/advisories/cesanta-mongoose-out-of-bounds-read-in-mg-tls-builtin-clienthello-session-id-parsingcnnvd
- https://github.com/cesanta/mongooseenisa_euvd
- https://github.com/cesanta/mongoose/releases/tag/7.22enisa_euvd
- https://github.com/cesanta/mongoosenvd
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