Case-Sensitive URL Prefix Bypass in Algernon Web Server by xyproto
CVE-2026-68548

9.4CRITICAL

Key Information:

Vendor

Xyproto

Status
Algernon
Vendor
CVE Published:
12 November 2026

What is CVE-2026-68548?

Algernon, a pure-Go web server developed by xyproto, is affected by a vulnerability that allows unauthorized access to protected areas. The issue arises from the case-sensitive matching of URL prefixes such as /admin, /repo, and /data. When a request containing a case-altered URL (e.g., /Admin/secret.lua) is made, the protection mechanism fails on case-insensitive filesystems like Windows NTFS and macOS APFS/HFS+, leading to an unintentional bypass of authorization checks. This vulnerability enables attackers to access or execute sensitive files in restricted directories. A patch has been released in version 1.17.10 to rectify this issue.

Affected Version(s)

algernon < 1.17.10

References

https://github.com/xyproto/algernon/security/advisories/G...
x_refsource_CONFIRM
https://github.com/xyproto/algernon/releases/tag/v1.17.10
x_refsource_MISC

CVSS V3.1

Score:
9.4
Severity:
CRITICAL
Confidentiality:
High
Integrity:
High
Availability:
High
Attack Vector:
Network
Attack Complexity:
Low
Privileges Required:
None
User Interaction:
None
Scope:
Unchanged

Timeline

  • Vulnerability published

  • Vulnerability Reserved

.