CVE•Published 2026-04-21•Modified 2026-06-30•1 article on news•6 live references•NVD data
CVE-2026-40611
Vulnerability data via NVD (ingested)
CVSS v3.1
8.8
HIGH
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
EPSS percentile
—
Weaknesses (CWE)
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.
Timeline
Published 2026-04-21
Modified 2026-06-30
External references
Search for exposed instances
Shodan + Censys queries derived from NVD's CPE data. The vuln tag catches assets Shodan has explicitly linked to this CVE; the product / banner fingerprints find exposed instances even when the vuln tag was never applied (which is common).
More intel sources (5)
Shodan report
vuln:CVE-2026-40611Country / ASN / product breakdown for the vuln query.
Censys
vulnerabilities.cve_id: CVE-2026-40611Censys host search filtered to this CVE id.
grep.app
CVE-2026-40611Public source-code mentions — fast PoC discovery.
GitHub code
CVE-2026-40611GitHub code search for direct mentions.
Google dork
"CVE-2026-40611" exploit -site:nvd.nist.govWrite-ups and news, NVD excluded.
Known PoCs on GitHub
No public proof-of-concept repositories found for CVE-2026-40611 on GitHub.