{"id":"CVE-2026-40611","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.","aliases":["GHSA-qqx8-2xmm-jrv8","GO-2026-5593"],"modified":"2026-07-24T19:11:21.379158072Z","published":"2026-04-21T17:58:35.221Z","related":["CGA-q9rr-8pq2-573m"],"database_specific":{"osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/40xxx/CVE-2026-40611.json","cna_assigner":"GitHub_M","cwe_ids":["CWE-22"]},"references":[{"type":"WEB","url":"https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-40611.json"},{"type":"ADVISORY","url":"https://access.redhat.com/errata/RHSA-2026:21772"},{"type":"ADVISORY","url":"https://access.redhat.com/security/cve/CVE-2026-40611"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/40xxx/CVE-2026-40611.json"},{"type":"ADVISORY","url":"https://github.com/go-acme/lego/security/advisories/GHSA-qqx8-2xmm-jrv8"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-40611"},{"type":"REPORT","url":"https://bugzilla.redhat.com/show_bug.cgi?id=2460233"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://github.com/go-acme/lego","events":[{"introduced":"0"},{"fixed":"f3c686a890e6fa36b92614112e8717832894faa7"}],"database_specific":{"source":"AFFECTED_FIELD","extracted_events":[{"introduced":"0"},{"fixed":"4.34.0"}]}}],"versions":["v4.33.0","v4.32.0","v4.31.0","v4.30.1","v4.29.0","v4.28.1","v4.28.0","v4.27.0","v4.26.0","v4.25.2","v4.25.1","v4.25.0","v4.24.0","v4.23.1","v4.23.0","v4.22.2","v4.22.1","v4.22.0","v4.21.0","v4.20.4","v4.20.3","v4.20.2","v4.20.1","v4.20.0","v4.19.2","v4.19.1","v4.19.0","v4.18.0","v4.17.4","v4.17.3","v4.17.2","v4.17.1","v4.17.0","v4.16.1","v4.16.0","v4.15.0","v4.14.2","v4.14.1","v4.14.0","v4.13.3","v4.13.2","v4.13.1","v4.13.0","v4.12.3","v4.12.2","v4.12.1","v4.12.0","v4.11.0","v4.10.2","v4.10.1","v4.10.0","v4.9.1","v4.9.0","v4.8.0","v4.7.0","v4.6.0","v4.5.3","v4.5.2","v4.5.1","v4.5.0","v4.4.0","v4.3.1","v4.3.0","v4.2.0","v4.1.3","v4.1.2","v4.1.1","v4.1.0","v4.0.1","v4.0.0","v3.9.0","v3.8.0","v3.7.0","v3.6.0","v3.5.0","v3.4.0","v3.3.0","v3.2.0","v3.1.0","v3.0.2","v3.0.0","v2.7.2","v2.7.1","v2.7.0","v2.6.0","v2.5.0","v2.4.0","v2.3.0","v2.2.0","v2.1.0","v2.0.1","v2.0.0","v1.2.1","v1.2.0","v1.1.0","v1.0.1","v1.0.0","v0.5.0","v0.4.1","v0.4.0","v0.3.1","v0.3.0","v0.2.0","v0.1.1","v0.1.0"],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-40611.json"}}],"schema_version":"1.7.5","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H"}]}