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.
References (2)
Core 2
Core References
X_Refsource_Confirm x_refsource_confirm
https://github.com/xyproto/algernon/security/advisories/GHSA-2j2c-pv62-mmcp
X_Refsource_Misc x_refsource_misc
https://github.com/xyproto/algernon/issues/172
Scores
CVSS v4
8.7
EPSS
0.0034
EPSS Percentile
26.1%
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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
CISA SSVC
Vulnrichment
Exploitation
none
Automatable
yes
Technical Impact
partial
Details
CWE
CWE-22
Status
published
Products (1)
xyproto/algernon
< 1.17.6
Published
May 26, 2026
Tracked Since
May 26, 2026