Vulnerability Details CVE-2026-73257
Mongoose is an embedded web server and network library. Priro to version 7.22, a remote unauthenticated attacker can send an HTTP request containing both Content-Length and Transfer-Encoding: chunked. The cl_count and te_count checks in the mg_http_parse() and http_cb() paths in src/http.c accept both headers and prioritize chunked encoding, while a Content-Length-preferring reverse proxy can use a different request boundary. This CL.TE desynchronization can inject requests that access or modify resources in another user context. This issue is fixed in version 7.22.
Exploit prediction scoring system (EPSS) score
EPSS Score 0.007
EPSS Ranking 50.1%
CVSS Severity
CVSS v3 Score 9.1
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-5wfq-r6mr-wqp6
- https://github.com/cesanta/mongoose/security/advisories/GHSA-5wfq-r6mr-wqp6
Products affected by CVE-2026-73257
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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