CVE-2026-68548: Auth Bypass (CVSS 9.4)

Description

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.

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CVSS v3.1 Score

9.4

CRITICAL

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

Weakness Type (CWE)

CWE-178 CWE-178

CWE-863 Incorrect Authorization

References

Other References

https://github.com/xyproto/algernon/releases/tag/v1.17.10 https://github.com/xyproto/algernon/security/advisories/GHSA-vm84-8c4p-64hx https://github.com/xyproto/algernon/security/advisories/GHSA-vm84-8c4p-64hx

Frequently Asked Questions

What is CVE-2026-68548? +

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. It has a CVSS v3.1 base score of 9.4 (CRITICAL).

How severe is CVE-2026-68548? +

CVE-2026-68548 has a CVSS v3.1 score of 9.4 out of 10, rated CRITICAL. This is a critical vulnerability that should be patched immediately.

How do I check if I'm vulnerable to CVE-2026-68548? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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