CVE-2026-43982

8.7 highEPSS 0.3%

High (8.7). EPSS 0.3% chance of exploitation in the next 30 days.

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.

Severity

CVSS 4.0

8.7 high

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: 0.3% chance of exploitation in the next 30 days; higher than 27% of CVEs (scores of 2026-10-31)
CWE: CWE-22
Published: 2026-05-26
Modified: 2026-07-24
Record from: the NVD, synced 2026-10-19

References

https://github.com/xyproto/algernon/issues/172
https://github.com/xyproto/algernon/security/advisories/GHSA-2j2c-pv62-mmcp

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