CVE-2026-40611
HIGH EPSS 22.6%
Published Apr 21, 20262mo ago · Modified Jun 17, 20262w ago
8.8 CVSS 3.1
Published Apr 21, 2026 2mo ago
Last Modified Jun 17, 2026 2w ago
Description
Let's Encrypt client and ACME library written in Go (Lego). Prior to 4.34.0, the webroot HTTP-01 challenge provider in lego is vulnerable to arbitrary file write and deletion via path traversal. A malicious ACME server can supply a crafted challenge token containing ../ sequences, causing lego to write attacker-influenced content to any path writable by the lego process. This vulnerability is fixed in 4.34.0.
CVSS Details
Base Score
Exploitability
Impact
Vector string
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H Attack Vector Network
Attack Complexity Low
Privileges Required None
User Interaction Required
Scope Unchanged
Confidentiality High
Integrity High
Availability High
Threat Intelligence
EPSS Exploit Probability
22.6% percentile
Exploit & Patch Status
No Known Exploit
No Patch Available
Weaknesses 1
CWE-22 Path Traversal Resource Mgmt
References 1
- github.com https://github.com/go-acme/lego/security/advisories/GHSA-qqx8-2xmm-jrv8
Remediation
No remediation data recorded yet
Check vendor advisories and the NVD entry for patch availability.