Algernon: Single-file mode unconditionally enables debug mode_CVE-2026-45728

7.5 / 10

HIGH

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

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.

Basic Information

ID CVE-2026-45728

Source GitHub_M

Published May 26, 2026 at 16:38

Affected Product

Vendor xyproto

Product algernon

Version < 1.17.7

Affected Versions xyproto algernon < 1.17.7

CWE Classification

CWE-209 CWE-489 CWE-540 CWE-1188

References

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

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    "published": "2026-05-26T16:38:50.435Z",
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