CVE-2026-73258

CVE-2026-73258 · Mongoose: Multipart boundary/header scan logic error in mg_http_next_multipart

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Mongoose is an embedded web server and network library. Prior to 7.22, a remote attacker can place a lone carriage return or line feed in multipart input processed by mg_http_next_multipart() in src/http.c. The loops comparing s[b] and s[b + 1], and s[h2] and s[h2 + 1], use an incorrect AND condition and stop when either character resembles part of a CRLF terminator. This truncates headers, filenames, or boundaries and can cause an application to accept dangerous content after seeing a misleading Content-Type value. This issue is fixed in version 7.22.

CVSS 6.5 · Medium · EPSS 0.5% · Fix available

Published

2026-08-20T17:36:39.239Z

Updated

2026-08-20T18:32:51.938Z

Stack: system

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