CVE-2026-40611

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Source
https://cve.org/CVERecord?id=CVE-2026-40611
Import Source
https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-40611.json
JSON Data
https://api.osv.dev/v1/vulns/CVE-2026-40611
Aliases
Downstream
Related
Published
2026-04-21T17:58:35.221Z
Modified
2026-07-24T19:11:21.379158072Z
Severity
  • 8.8 (High) CVSS_V3 - CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H CVSS Calculator
Summary
Lego: Arbitrary File Write via Path Traversal in Webroot HTTP-01 Provider
Details

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.

Database specific 
{
    "cwe_ids": [
        "CWE-22"
    ],
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/40xxx/CVE-2026-40611.json",
    "cna_assigner": "GitHub_M"
}
References

Affected packages

Git / github.com/go-acme/lego

Affected ranges

Type
GIT
Repo
https://github.com/go-acme/lego
Events
Introduced
0 Unknown introduced commit / All previous commits are affected
Fixed
f3c686a890e6fa36b92614112e8717832894faa7
Database specific 
{
    "source": "AFFECTED_FIELD",
    "extracted_events": [
        {
            "introduced": "0"
        },
        {
            "fixed": "4.34.0"
        }
    ]
}

Affected versions

v0.*
v0.1.0
v0.1.1
v0.2.0
v0.3.0
v0.3.1
v0.4.0
v0.4.1
v0.5.0
v1.*
v1.0.0
v1.0.1
v1.1.0
v1.2.0
v1.2.1
v2.*
v2.0.0
v2.0.1
v2.1.0
v2.2.0
v2.3.0
v2.4.0
v2.5.0
v2.6.0
v2.7.0
v2.7.1
v2.7.2
v3.*
v3.0.0
v3.0.2
v3.1.0
v3.2.0
v3.3.0
v3.4.0
v3.5.0
v3.6.0
v3.7.0
v3.8.0
v3.9.0
v4.*
v4.0.0
v4.0.1
v4.1.0
v4.1.1
v4.1.2
v4.1.3
v4.10.0
v4.10.1
v4.10.2
v4.11.0
v4.12.0
v4.12.1
v4.12.2
v4.12.3
v4.13.0
v4.13.1
v4.13.2
v4.13.3
v4.14.0
v4.14.1
v4.14.2
v4.15.0
v4.16.0
v4.16.1
v4.17.0
v4.17.1
v4.17.2
v4.17.3
v4.17.4
v4.18.0
v4.19.0
v4.19.1
v4.19.2
v4.2.0
v4.20.0
v4.20.1
v4.20.2
v4.20.3
v4.20.4
v4.21.0
v4.22.0
v4.22.1
v4.22.2
v4.23.0
v4.23.1
v4.24.0
v4.25.0
v4.25.1
v4.25.2
v4.26.0
v4.27.0
v4.28.0
v4.28.1
v4.29.0
v4.3.0
v4.3.1
v4.30.1
v4.31.0
v4.32.0
v4.33.0
v4.4.0
v4.5.0
v4.5.1
v4.5.2
v4.5.3
v4.6.0
v4.7.0
v4.8.0
v4.9.0
v4.9.1

Database specific

source 
"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-40611.json"