mongoose: Mongoose is an embedded web server and network library
CVE-2026-73261 is fixed in mongoose on 1 platform by DEBIAN-CVE-2026-73261 (version 7.23+ds-1), released August 19, 2026. It is not reported as exploited. Patch Radar priority: High.
Mongoose is an embedded web server and network library. Prior to 7.23, the built-in TCP/IP stack enabled by MG_ENABLE_TCPIP in src/net_builtin.c does not reject a TCP option whose declared opts[1] length exceeds the remaining option bytes. In handle_opt(), a NOP followed by a truncated MSS option causes opts[3] to be read outside the declared options area and used as the low byte of dmss. An unauthenticated remote peer can corrupt the per-connection MSS value so later mg_send() calls transmit truncated or zero-length application payloads while the TCP connection otherwise appears healthy. This issue is fixed in version 7.23.
Where it's fixed
| Product | Fixed in | Fix | Released |
|---|---|---|---|
| Linux | |||
| mongoose · Debian 14 | 7.23+ds-1 | DEBIAN-CVE-2026-73261 | Aug 19, 2026 |
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