CVE-2026-40611
Lego: Arbitrary File Write via Path Traversal in Webroot HTTP-01 Provider
- State
- Published
- Severity
- 8.8 High
- Published
- Apr 21, 2026
- Updated
- Jul 15, 2026
- Reserved
- Apr 14, 2026
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.
Scores
| CVSS | Score | Vector | Source |
|---|---|---|---|
| 3.1 | 8.8 High | CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H | GitHub_M |
| 3.1 | 8.8 High | CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H | redhat-SADP |
Weaknesses
- CWE-22 Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')
Affected Products
| Product | Versions |
|---|---|
legogo-acme |
|
References
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