CVE-2026-73261 Mongoose: handle_opt() missing opts[1] > len check — 1-byte OOB read corrupts TCP MSS, silences mg_send() per connection

Mongoose is an embedded web server and network library. Prior to 7.23, the built-in TCP/IP stack enabled by MGENABLETCPIP in src/netbuiltin.c does not reject a TCP option whose declared opts1 length exceeds the remaining option bytes. In handleopt, a NOP followed by a truncated MSS option causes...

CVE-2026-73261 Mongoose: handle_opt() missing opts[1] > len check — 1-byte OOB read corrupts TCP MSS, silences mg_send() per connection

Mongoose is an embedded web server and network library. Prior to 7.23, the built-in TCP/IP stack enabled by MGENABLETCPIP in src/netbuiltin.c does not reject a TCP option whose declared opts1 length exceeds the remaining option bytes. In handleopt, a NOP followed by a truncated MSS option causes...

CVE-2026-73261 Mongoose: handle_opt() missing opts[1] > len check — 1-byte OOB read corrupts TCP MSS, silences mg_send() per connection

Mongoose is an embedded web server and network library. Prior to 7.23, the built-in TCP/IP stack enabled by MGENABLETCPIP in src/netbuiltin.c does not reject a TCP option whose declared opts1 length exceeds the remaining option bytes. In handleopt, a NOP followed by a truncated MSS option causes...

CVE-2026-73261

The Mongoose embedded web server and network library (versions prior to 7.23 ) contains a vulnerability in its built-in TCP/IP stack. Specifically, the handle_opt() function in src/net_builtin.c fails to validate that the opts[1] length of a TCP option does not exceed the remaining option bytes. ...