CVE-2026-43982 HIGH

CVE-2026-43982: Algernon: Path traversal file write via savein()

Vendor Xyproto
Product algernon
Weakness CWE-22 · Path traversal
Published May 26, 2026
Last update May 26, 2026
View on NVD All CVEs

CVSS base score

8.7/10
Attack vector Network
Attack complexity Low
Privileges required None
User interaction None
Confidentiality —
Integrity —

CVSS vector

CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N

What the vulnerability does

01Description

Algernon is a small self-contained pure-Go web server. Prior to 1.17.6, uploadedFileSaveIn() in lua/upload/upload.go uses filepath.Join() with the caller-supplied directory but performs no boundary check after joining. A directory of ../../../tmp resolves cleanly to /tmp, outside the web root. This vulnerability is fixed in 1.17.6.

Key dates

02Disclosure timeline

May 26, 2026 CVE published
May 26, 2026 Record updated