Out-of-bounds Read Affecting cesanta/mongoose package, versions [,7.23)
Threat Intelligence
Snyk has a proof-of-concept or detailed explanation of how to exploit this vulnerability.
The probability is the direct output of the EPSS model, and conveys an overall sense of the threat of exploitation in the wild. The percentile measures the EPSS probability relative to all known EPSS scores. Note: This data is updated daily, relying on the latest available EPSS model version. Check out the EPSS documentation for more details.
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Test your applications- Snyk IDSNYK-UNMANAGED-CESANTAMONGOOSE-20948706
- published15 Oct 2026
- disclosed14 Oct 2026
- creditHuihui Huang
Introduced: 14 Oct 2026
NewCVE-2026-73260 (opens in a new tab)How to fix?
Upgrade cesanta/mongoose to version 7.23 or higher.
Overview
cesanta/mongoose is a networking library for C/C++. It implements event-driven non-blocking APIs for TCP, UDP, HTTP, WebSocket, MQTT.
Affected versions of this package are vulnerable to Out-of-bounds Read in the mg_der_to_tlv function, whose long-form length branch validates the count of length octets but never checks the decoded content length against the remaining buffer, so mg_der_parse can report more bytes consumed than the enclosing element holds and the parent->len -= (uint32_t) consumed subtraction in mg_der_next underflows. An attacker acting as a TLS peer can crash the process by presenting an X.509 certificate in which an element declares a long-form length exceeding its parent, after which parent->value points past the buffer and mg_tls_parse_cert_der keeps advancing that pointer forward through memory on each iteration. This affects builds with MG_TLS set to MG_TLS_BUILTIN, requires a target with an MMU for the read to fault, and is reachable in both directions, against a client from a server or MitM position and against a server that requests and parses client certificates, since the preceding certificate message unpacking validates only the chain and per-certificate length framing.