CVE-2026-73255: medium-severity vulnerability in cesanta mongoose
Mongoose: Path traversal in SSI #include directives enables arbitrary file read
Published · Updated
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13Vexday Risk Score
No sign of exploitation. No public exploitation artifact known so far.
ssvc Trackcvss 6.5epss 0.7%
Mongoose is an embedded web server and network library. Prior to 7.22, an attacker who can control an SSI-enabled file can place directory traversal sequences in an #include file or #include virtual directive. The mg_ssi() function in src/ssi.c concatenates the directive argument into a filesystem path without calling mg_path_is_sane(), allowing an MG_ENABLE_SSI deployment with ssi_pattern configured to disclose files readable by the Mongoose process. This issue is fixed in version 7.22.
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N
Affected products
cesanta · mongooseRelated CVEs — cesanta mongoose
In the same product, most dangerous first.
CVE-2026-73257CRITICALMongoose: Content-Length + Transfer-Encoding coexistence enables request smugglingEPSS 0.7%CVE-2026-73258MEDIUMMongoose: Multipart boundary/header scan logic error in mg_http_next_multipartEPSS 0.5%CVE-2026-73256CRITICALMongoose: HTTP/1.0 detection off-by-one enables request smuggling via chunked TEEPSS 0.4%CVE-2026-73261HIGHMongoose: handle_opt() missing opts[1] > len check — 1-byte OOB read corrupts TCP MSS, silences mg_send() per connectionEPSS 0.4%CVE-2026-73259MEDIUMMongoose: Reflected XSS via decoded URI in directory listing renderEPSS 0.4%CVE-2026-73252HIGHMongoose: Unauthenticated remote heap out-of-bounds read in built-in TLS: off-by-one length check in mg_tls_recv_record() underflows recv_len to SIZE_MAXEPSS 0.4%