CVE-2026-73260: CWE-125: Out-of-bounds Read in cesanta mongoose
Description
Mongoose is an embedded web server and network library. Prior to 7.23, the built-in TLS certificate parser selected by MG_TLS_BUILTIN fails to verify that a long-form DER element length fits within the remaining certificate buffer. In mg_der_to_tlv() and mg_der_next(), a peer-controlled length can advance the parser beyond the certificate and underflow the remaining uint32_t length, causing mg_tls_parse_cert_der() to continue walking an invalid pointer. An unauthenticated malicious TLS server, or a client presenting a certificate to a server configured for client certificates, can trigger an out-of-bounds read and denial of service during the handshake. This issue is fixed in version 7.23.
CVSS v3.1
Score 7.5high
Affected software
cesanta
mongoose
Weaknesses
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- GitHub_M
- Date Reserved
- 2026-08-11T17:18:01.598Z
- Cvss Version
- 3.1
- State
- PUBLISHED
Threat ID: 6acfceae2cdf04f656a1f7e4
Added to database: 10/14/2026, 18:49:18 UTC
Last updated: 10/14/2026, 18:49:18 UTC
Views: 1
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