CVE-2026-43982CWE-22

Algernon: Path traversal file write via savein()

High · published May 26, 2026

CVSS v4.0
8.7
EPSS
1%
Percentile
43.0
In the wild
Unconfirmed
What it is

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.

The record
Technical detail
CVSS v4.0
8.7 · HIGH
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
EPSS
0.00515 · 43.0th percentile
Weakness
CWE-22 · Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')
Published
2026-05-26T16:30Z
EPSS history
Timeline
  • 26 MAY 16:30Z
    Algernon: Path traversal file write via savein()
    cvelistv5