CVE-2026-73255: CWE-22: Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal') in cesanta mongoose
Description
CVE-2026-73255 is a path traversal vulnerability in the cesanta mongoose embedded web server and network library. Versions prior to 7.22 allow an attacker who can control an SSI-enabled file to include directory traversal sequences in #include directives. This leads to disclosure of files readable by the Mongoose process due to improper sanitization of the file path. The issue is fixed in version 7.22.
CVSS v3.1
Score 6.5medium
Affected software
cesanta
mongoose
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Weaknesses
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
Mongoose versions before 7.22 contain a path traversal vulnerability (CWE-22) in the mg_ssi() function located in src/ssi.c. The function concatenates the argument of #include or #include virtual directives into a filesystem path without validating it via mg_path_is_sane(). An attacker controlling an SSI-enabled file can exploit this by inserting directory traversal sequences, potentially disclosing arbitrary files accessible by the Mongoose process. This vulnerability is resolved in version 7.22.
Potential Impact
An attacker with the ability to control an SSI-enabled file can exploit this vulnerability to read arbitrary files accessible by the Mongoose process. This results in a confidentiality breach but does not affect integrity or availability. The CVSS 3.1 base score is 6.5 (medium severity), reflecting network attack vector, low attack complexity, required privileges, no user interaction, unchanged scope, high confidentiality impact, and no integrity or availability impact.
Mitigation Recommendations
Upgrade to Mongoose version 7.22 or later where this vulnerability is fixed. No other mitigation is indicated by the vendor advisory.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- GitHub_M
- Date Reserved
- 2026-08-11T17:18:01.598Z
- Cvss Version
- 3.1
- State
- PUBLISHED
Threat ID: 6a873eeeacd9273b49f2b5e4
Added to database: 08/20/2026, 17:52:46 UTC
Last enriched: 09/11/2026, 04:18:45 UTC
Last updated: 10/04/2026, 18:53:18 UTC
Views: 63
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