Directory Traversal Vulnerability in Algernon Web Server by XYPROTO
CVE-2026-43982

8.7HIGH

Key Information:

Vendor

Xyproto

Status
Algernon
Vendor
CVE Published:
26 May 2026

What is CVE-2026-43982?

Algernon, a self-contained pure-Go web server, has a directory traversal vulnerability that allows attackers to access files outside the intended web root. This occurs in the uploadedFileSaveIn() function prior to version 1.17.6, where improper boundary checks after using filepath.Join() can lead to exposure of sensitive data. An attacker can exploit this by constructing a directory path that resolves to locations outside the safe directory, such as ../../../tmp, compromising server security. Users are advised to update to version 1.17.6 or later to mitigate this risk.

Affected Version(s)

algernon < 1.17.6

References

https://github.com/xyproto/algernon/security/advisories/G...
x_refsource_CONFIRM
https://github.com/xyproto/algernon/issues/172
x_refsource_MISC

CVSS V4

Score:
8.7
Severity:
HIGH
Confidentiality:
None
Integrity:
High
Availability:
None
Attack Vector:
Network
Attack Complexity:
Low
Attack Required:
None
Privileges Required:
Undefined
User Interaction:
None

Timeline

  • Vulnerability published

  • Vulnerability Reserved

.