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HIGH · 8.2

CVE-2026-48126

Algernon is a small self-contained pure-Go web server. Prior to 1.17.8, when algernon is started with --domain (or --letsencrypt, which silently turns on --domain at engine/flags.go:372), the request ...

Vulnerability Description

Algernon is a small self-contained pure-Go web server. Prior to 1.17.8, when algernon is started with --domain (or --letsencrypt, which silently turns on --domain at engine/flags.go:372), the request handler resolves the served directory by joining the configured --dir with the value of the client-supplied Host header. The join is performed by filepath.Join with no validation, so a Host: .. header walks one level above the document root. Subsequent file resolution then exposes everything in that parent directory — arbitrary file read, full directory listing, and, if any .lua file is present, server-side Lua execution. This vulnerability is fixed in 1.17.8.

CVSS Score

8.2

HIGH

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:L/A:N
Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
HIGH
Integrity
LOW
Availability
NONE

Related Weaknesses (CWE)

CWE-22CWE-23CWE-644

References

FAQ

What is CVE-2026-48126?

CVE-2026-48126 is a vulnerability with a CVSS score of 8.2 (HIGH). Algernon is a small self-contained pure-Go web server. Prior to 1.17.8, when algernon is started with --domain (or --letsencrypt, which silently turns on --domain at engine/flags.go:372), the request ...

How severe is CVE-2026-48126?

CVE-2026-48126 has been rated HIGH with a CVSS base score of 8.2/10. Review the CVSS metrics above for detailed severity breakdown.

Is there a patch for CVE-2026-48126?

Check the references section above for vendor advisories and patch information. Review vendor security bulletins for remediation guidance.