xyproto Algernon up to 1.17.9 URL-prefix authorization gate /Admin/secret.lua strings.HasPrefix improper authorization

Summaryinfo

A vulnerability has been found in xyproto Algernon up to 1.17.9 and classified as critical. The impacted element is the function strings.HasPrefix of the file /Admin/secret.lua of the component URL-prefix authorization gate. Performing a manipulation results in improper authorization. This vulnerability is cataloged as CVE-2026-68548. It is possible to initiate the attack remotely. There is no exploit available. The affected component should be upgraded.

Detailsinfo

A vulnerability classified as critical has been found in xyproto Algernon up to 1.17.9. This affects the function strings.HasPrefix of the file /Admin/secret.lua of the component URL-prefix authorization gate. The manipulation with an unknown input leads to a improper authorization vulnerability. CWE is classifying the issue as CWE-285. The product does not perform or incorrectly performs an authorization check when an actor attempts to access a resource or perform an action. This is going to have an impact on confidentiality, integrity, and availability. The summary by CVE is:

Algernon is a small self-contained pure-Go web server. Prior to version 1.17.10, Algernon's URL-prefix authorization gate matches its protected prefixes (/admin, /repo, /data) with case-sensitive strings.HasPrefix, while the exact same raw req.URL.Path is later resolved against the filesystem. On case-insensitive filesystems (Windows NTFS — always; macOS APFS/HFS+ — default), a request for /Admin/secret.lua evades every protected-prefix check, falls through to the public-prefix accept branch, and then resolves on disk to admin/secret.lua. The result is an unauthenticated bypass of the /admin, /repo, and /data authorization boundary, enabling read (and, for Lua files, execution) of protected content. The permission system is active in the default configuration. This issue has been patched in version 1.17.10.

The advisory is shared at github.com. This vulnerability is uniquely identified as CVE-2026-68548 since 07/30/2026. The exploitability is told to be easy. It is possible to initiate the attack remotely. No form of authentication is needed for exploitation. Technical details are known, but no exploit is available. MITRE ATT&CK project uses the attack technique T1548.002 for this issue.

Upgrading to version 1.17.10 eliminates this vulnerability.

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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
• 1.17.7
• 1.17.8
• 1.17.9

Website

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

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