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Vulnerability record · CVE-2026-45728 · published 26 May 2026

CVE-2026-45728: Error message information leak vulnerability

Algernon is a small self-contained pure-Go web server. Prior to 1.17.7, when Algernon is invoked with a single file path instead of a directory, singleFileMode is set to true and debugMode is forcibly enabled. debugMode activates the PrettyError renderer, which on any Lua or template error response dumps the absolute path of the file that errored, complete byte contents of that file, and exception or parser error text. This response is served with HTTP 200 OK to whoever sent the request that triggered the error. Any client able to reach the server and able to provoke a runtime error in the served script obtains the full server-side source of that script and of any sibling Lua data file consulted during the request. This vulnerability is fixed in 1.17.7.

7.5 CVSS 3.1 High EPSS 0.42% · top 66.7% CWE-209 · Error message information leakCWE-489 · CWE-489 Deferred
7.5CVSS 3.1 base score
0.42%EPSS exploitation probability, 30 days
NoNot in CISA KEV
0Affected product versions listed by NVD
2References
24 Jul 2026Last modified by NVD

Description

Algernon is a small self-contained pure-Go web server. Prior to 1.17.7, when Algernon is invoked with a single file path instead of a directory, singleFileMode is set to true and debugMode is forcibly enabled. debugMode activates the PrettyError renderer, which on any Lua or template error response dumps the absolute path of the file that errored, complete byte contents of that file, and exception or parser error text. This response is served with HTTP 200 OK to whoever sent the request that triggered the error. Any client able to reach the server and able to provoke a runtime error in the served script obtains the full server-side source of that script and of any sibling Lua data file consulted during the request. This vulnerability is fixed in 1.17.7.

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N

References

LinkTags
https://github.com/xyproto/algernon/security/advisories/GHSA-fwqx-8365-9983
https://github.com/xyproto/algernon/security/advisories/GHSA-fwqx-8365-9983

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Source: NIST National Vulnerability Database (record CVE-2026-45728), CISA KEV, FIRST EPSS (scores of 2026-09-26). This page is refreshed as NVD updates the record.