Vulnerability Details CVE-2026-73258
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.
Exploit prediction scoring system (EPSS) score
EPSS Score 0.005
EPSS Ranking 37.3%
CVSS Severity
CVSS v3 Score 6.5
References
- https://github.com/cesanta/mongoose/commit/a9df523f76f43a38bd53b4232b9cfd4c16869e71
- https://github.com/cesanta/mongoose/pull/3611
- https://github.com/cesanta/mongoose/releases/tag/7.22
- https://github.com/cesanta/mongoose/security/advisories/GHSA-cc55-8v3r-59p8
- https://github.com/cesanta/mongoose/security/advisories/GHSA-cc55-8v3r-59p8
Products affected by CVE-2026-73258
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cpe:2.3:a:cesanta:mongoose:-
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cpe:2.3:a:cesanta:mongoose:3.2
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cpe:2.3:a:cesanta:mongoose:3.3
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cpe:2.3:a:cesanta:mongoose:3.4
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cpe:2.3:a:cesanta:mongoose:3.5
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cpe:2.3:a:cesanta:mongoose:3.6
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cpe:2.3:a:cesanta:mongoose:3.7
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cpe:2.3:a:cesanta:mongoose:3.8
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cpe:2.3:a:cesanta:mongoose:4.0
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cpe:2.3:a:cesanta:mongoose:4.1
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cpe:2.3:a:cesanta:mongoose:5.0
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cpe:2.3:a:cesanta:mongoose:5.1
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cpe:2.3:a:cesanta:mongoose:5.2
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cpe:2.3:a:cesanta:mongoose:5.3
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cpe:2.3:a:cesanta:mongoose:5.4
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cpe:2.3:a:cesanta:mongoose:5.5
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cpe:2.3:a:cesanta:mongoose:5.6
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cpe:2.3:a:cesanta:mongoose:6.0
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cpe:2.3:a:cesanta:mongoose:6.1
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cpe:2.3:a:cesanta:mongoose:6.10
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cpe:2.3:a:cesanta:mongoose:6.11
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cpe:2.3:a:cesanta:mongoose:6.12
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cpe:2.3:a:cesanta:mongoose:6.13
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cpe:2.3:a:cesanta:mongoose:6.14
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cpe:2.3:a:cesanta:mongoose:6.15
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cpe:2.3:a:cesanta:mongoose:6.16
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cpe:2.3:a:cesanta:mongoose:6.17
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cpe:2.3:a:cesanta:mongoose:6.18
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cpe:2.3:a:cesanta:mongoose:6.2
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cpe:2.3:a:cesanta:mongoose:6.3
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cpe:2.3:a:cesanta:mongoose:6.4
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cpe:2.3:a:cesanta:mongoose:6.5
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cpe:2.3:a:cesanta:mongoose:6.6
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cpe:2.3:a:cesanta:mongoose:6.7
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cpe:2.3:a:cesanta:mongoose:6.8
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cpe:2.3:a:cesanta:mongoose:6.9
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cpe:2.3:a:cesanta:mongoose:7.0
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cpe:2.3:a:cesanta:mongoose:7.1
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cpe:2.3:a:cesanta:mongoose:7.10
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cpe:2.3:a:cesanta:mongoose:7.11
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cpe:2.3:a:cesanta:mongoose:7.12
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cpe:2.3:a:cesanta:mongoose:7.13
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cpe:2.3:a:cesanta:mongoose:7.14
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cpe:2.3:a:cesanta:mongoose:7.15
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cpe:2.3:a:cesanta:mongoose:7.16
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cpe:2.3:a:cesanta:mongoose:7.17
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cpe:2.3:a:cesanta:mongoose:7.18
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cpe:2.3:a:cesanta:mongoose:7.19
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cpe:2.3:a:cesanta:mongoose:7.2
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cpe:2.3:a:cesanta:mongoose:7.20
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cpe:2.3:a:cesanta:mongoose:7.21
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cpe:2.3:a:cesanta:mongoose:7.3
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cpe:2.3:a:cesanta:mongoose:7.4
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cpe:2.3:a:cesanta:mongoose:7.5
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cpe:2.3:a:cesanta:mongoose:7.6
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cpe:2.3:a:cesanta:mongoose:7.7
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cpe:2.3:a:cesanta:mongoose:7.8
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cpe:2.3:a:cesanta:mongoose:7.9