Path Traversal in Xyproto Algernon
CVE-2026-43982
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.
Vulnerability class: Path Traversal (Directory Traversal)
Published · last modified .
EPSS exploit prediction
EPSS: 0.005 (42.7th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 43rd percentile — 42.7% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.003 · newest: 0.005 · change: +0.002
Affected products
- Xyproto Algernon — versions < 1.17.6