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.

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Advisories
Source ID Title
Github GHSA Github GHSA GHSA-fwqx-8365-9983 Algernon: Single-file mode unconditionally enables debug mode
Fixes

Solution

No solution given by the vendor.


Workaround

No workaround given by the vendor.

History

Tue, 26 May 2026 18:30:00 +0000

Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'yes', 'Exploitation': 'poc', 'Technical Impact': 'partial'}, 'version': '2.0.3'}


Tue, 26 May 2026 17:00:00 +0000

Type Values Removed Values Added
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.
Title Algernon: Single-file mode unconditionally enables debug mode
Weaknesses CWE-1188
CWE-209
CWE-489
CWE-540
References
Metrics cvssV3_1

{'score': 7.5, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N'}


Projects

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cve-icon MITRE

Status: PUBLISHED

Assigner: GitHub_M

Published:

Updated: 2026-05-26T17:31:40.280Z

Reserved: 2026-05-13T05:51:48.667Z

Link: CVE-2026-45728

cve-icon Vulnrichment

Updated: 2026-05-26T17:30:50.618Z

cve-icon NVD

Status : Received

Published: 2026-05-26T17:16:47.900

Modified: 2026-05-26T18:16:52.193

Link: CVE-2026-45728

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

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