If left unpatched, CVE-2026-73255 could lead to major system disruptions or data loss.
Status: Analyzed
Last updated: 🕞 29 Sep 2026, 15:39 UTC
Originally published on: 🕕 20 Aug 2026, 18:16 UTC
Time between publication and last update: 39 days
CVSS Release: version 3
security-advisories@github.com
Secondary
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N
CVE-2026-73255: 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.
The exploitability of CVE-2026-73255 depends on two key factors: attack complexity (the level of effort required to execute an exploit) and privileges required (the access level an attacker needs).
CVE-2026-73255 presents an accessible attack vector with minimal effort required. Restricting access controls and implementing security updates are critical to reducing exploitation risks.
A lower complexity and fewer privilege requirements make exploitation easier. Security teams should evaluate these aspects to determine the urgency of mitigation strategies, such as patch management and access control policies.
Attack Complexity (AC) measures the difficulty in executing an exploit. A high AC means that specific conditions must be met, making an attack more challenging, while a low AC means the vulnerability can be exploited with minimal effort.
Privileges Required (PR) determine the level of system access necessary for an attack. Vulnerabilities requiring no privileges are more accessible to attackers, whereas high privilege requirements limit exploitation to authorized users with elevated access.
Above is the CVSS Sub-score Breakdown for CVE-2026-73255, illustrating how Base, Impact, and Exploitability factors combine to form the overall severity rating. A higher sub-score typically indicates a more severe or easier-to-exploit vulnerability.
Below is the Impact Analysis for CVE-2026-73255, showing how Confidentiality, Integrity, and Availability might be affected if the vulnerability is exploited. Higher values usually signal greater potential damage.
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