CVE-2026-45728: CWE-209: Generation of Error Message Containing Sensitive Information in xyproto algernon
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.
AI Analysis
Technical Summary
Algernon, a pure-Go web server, prior to version 1.17.7, enables debugMode automatically when invoked with a single file path (singleFileMode). Debug mode activates the PrettyError renderer, which on Lua or template errors returns detailed error responses including the absolute path, complete byte contents of the errored file, and exception or parser error text. These responses are served with HTTP 200 OK status to any client causing the error, allowing disclosure of server-side source code and related Lua data files. This information leak vulnerability is tracked as CVE-2026-45728 and is resolved in version 1.17.7.
Potential Impact
An unauthenticated remote attacker able to provoke a runtime error in the served Lua or template scripts can obtain full server-side source code and sensitive file contents. This disclosure can aid further attacks or intellectual property theft. The vulnerability does not affect integrity or availability directly but results in a high confidentiality impact. No known exploits are reported in the wild.
Mitigation Recommendations
Upgrade to Algernon version 1.17.7 or later, where this issue is fixed. Prior versions forcibly enable debug mode in single file mode causing sensitive information disclosure. No other official remediation or temporary fixes are documented. Patch status is not explicitly stated but the vendor fixed the issue in 1.17.7, so upgrading is the recommended action.
CVE-2026-45728: CWE-209: Generation of Error Message Containing Sensitive Information in xyproto algernon
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 v3.1
Score 7.5high
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
Algernon, a pure-Go web server, prior to version 1.17.7, enables debugMode automatically when invoked with a single file path (singleFileMode). Debug mode activates the PrettyError renderer, which on Lua or template errors returns detailed error responses including the absolute path, complete byte contents of the errored file, and exception or parser error text. These responses are served with HTTP 200 OK status to any client causing the error, allowing disclosure of server-side source code and related Lua data files. This information leak vulnerability is tracked as CVE-2026-45728 and is resolved in version 1.17.7.
Potential Impact
An unauthenticated remote attacker able to provoke a runtime error in the served Lua or template scripts can obtain full server-side source code and sensitive file contents. This disclosure can aid further attacks or intellectual property theft. The vulnerability does not affect integrity or availability directly but results in a high confidentiality impact. No known exploits are reported in the wild.
Mitigation Recommendations
Upgrade to Algernon version 1.17.7 or later, where this issue is fixed. Prior versions forcibly enable debug mode in single file mode causing sensitive information disclosure. No other official remediation or temporary fixes are documented. Patch status is not explicitly stated but the vendor fixed the issue in 1.17.7, so upgrading is the recommended action.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- GitHub_M
- Date Reserved
- 2026-05-13T05:51:48.667Z
- Cvss Version
- 3.1
- State
- PUBLISHED
- Remediation Level
- null
Threat ID: 6a15d22e891d628fdc600897
Added to database: 5/26/2026, 5:02:38 PM
Last enriched: 5/26/2026, 5:17:58 PM
Last updated: 5/26/2026, 9:49:56 PM
Views: 2
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