SB2026041649 - Path traversal in lego
Published: April 16, 2026
Security Bulletin ID
SB2026041649
Severity
High
Patch available
YES
Number of vulnerabilities
1
Exploitation vector
Remote access
Highest impact
Code execution
Breakdown by Severity
- Low
- Medium
- High
- Critical
Description
This security bulletin contains information about 1 security vulnerability.
1) Path traversal (CVE-ID: CVE-2026-40611)
The vulnerability allows a remote attacker to write or delete arbitrary files.
The vulnerability exists due to path traversal in the webroot HTTP-01 challenge provider when processing a crafted ACME challenge token. A remote attacker can supply a token containing traversal sequences to write or delete arbitrary files.
User interaction is required to run lego against a malicious or compromised ACME server with the HTTP-01 webroot challenge solver enabled.
Remediation
Install update from vendor's website.