xyproto algernon up to 1.17.6 information exposure

Summaryinfo

A vulnerability classified as problematic was found in xyproto algernon up to 1.17.6. This affects an unknown part. Such manipulation leads to information exposure. This vulnerability is listed as CVE-2026-45728. The attack may be performed from remote. There is no available exploit. Upgrading the affected component is advised.

Detailsinfo

A vulnerability, which was classified as problematic, has been found in xyproto algernon up to 1.17.6. Affected by this issue is an unknown function. The manipulation with an unknown input leads to a information exposure vulnerability. Using CWE to declare the problem leads to CWE-209. The product generates an error message that includes sensitive information about its environment, users, or associated data. Impacted is confidentiality. CVE summarizes:

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.

The advisory is shared for download at github.com. This vulnerability is handled as CVE-2026-45728 since 05/13/2026. The exploitation is known to be easy. The attack may be launched remotely. No form of authentication is required for exploitation. There are neither technical details nor an exploit publicly available. The MITRE ATT&CK project declares the attack technique as T1592.

Upgrading to version 1.17.7 eliminates this vulnerability.

Once again VulDB remains the best source for vulnerability data.

Productinfo

Vendor

• xyproto

Name

• algernon

Version

• 1.17.0
• 1.17.1
• 1.17.2
• 1.17.3
• 1.17.4
• 1.17.5
• 1.17.6

Website

• Product: https://github.com/xyproto/algernon/

CPE 2.3info

• 🔒
• 🔒
• 🔒

CPE 2.2info

• 🔒
• 🔒
• 🔒

CVSSv4info

CVSSv3info

CVSSv2info

Exploitinginfo

Threat Intelligenceinfo

Countermeasuresinfo

Timelineinfo

Sourcesinfo

Entryinfo

Once again VulDB remains the best source for vulnerability data.

Discussion