Vulnerability · Published May 26, 2026 · Assigned by GitHub_M
CVE-2026-43982Algernon: Path traversal file write via savein()
High 8.7
In plain English
A high-severity path traversal in algernon from xyproto. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.3% (higher than 28% of all known vulnerabilities).
Severity (CVSS 4.0)8.7High
Exploit odds (30 days)0.3%top 71.9% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack toolingNoneno public tooling known
Official description
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.
Affected products (as reported)
Weakness: CWE-22 · 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
References
- https://github.com/xyproto/algernon/security/advisories/GHSA-2j2c-pv62-mmcp x_refsource_CONFIRM
- https://github.com/xyproto/algernon/issues/172 x_refsource_MISC