CVE catalog
CVE-2026-40611
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 mal
- Severity
- High · CVSS 8.8
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H - Published
- Source
- [NVD] · [CVE record]
- EPSS
- 0.34% · Oct 25, 2026
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.
Vulnerable and fixed packages
Distribution-reported package versions and fixes. These do not depend on matching against the OpenFactory package catalog.
| Distribution | Package | Release | Version | Status |
|---|---|---|---|---|
| Debian | golang-github-xenolf-lego | sid | 4.35.2-3 | fixed |
| Debian | golang-github-xenolf-lego | forky | 4.35.2-3 | fixed |
| Debian | golang-github-xenolf-lego | trixie | 4.9.1-2 | vulnerable |
| Debian | golang-github-xenolf-lego | bookworm | 4.9.1-1 | vulnerable |
| Cpe | golang-github-xenolf-lego | Not reported | Not reported | vulnerable |
Fixed-version evidence
| Distribution | Package | Type | Release | Fixed version | Urgency | Origin | Bugs |
|---|---|---|---|---|---|---|---|
| Debian | golang-github-xenolf-lego | source | sid | 4.35.2-1 | not yet assigned | Not reported | [1134643] |
| Debian | golang-github-xenolf-lego | source | forky | 4.35.2-1 | not yet assigned | Not reported | [1134643] |
| Debian | golang-github-xenolf-lego | source | trixie | (unfixed) | not yet assigned | Not reported | [1134643] |
| Debian | golang-github-xenolf-lego | source | bookworm | (unfixed) | not yet assigned | Not reported | [1134643] |
Notes
[trixie] golang-github-xenolf-lego: Minor issue [bookworm] golang-github-xenolf-lego: Minor issue
OpenFactory catalog packages
[Debian 12 (Bookworm)]
- [golang-github-xenolf-lego-dev]Affected
Source package: [golang-github-xenolf-lego]
Details (2)
4.9.1-1· all · bookwormAffected
nvd · golang-github-xenolf-lego · debian · bookworm; nvd · golang-github-xenolf-lego · debian · 12
4.9.1-1· all · bookwormAffected
nvd · golang-github-xenolf-lego · debian · bookworm; nvd · golang-github-xenolf-lego · debian · 12
- [lego]Affected
Source package: [golang-github-xenolf-lego]
Details (2)
4.9.1-1· amd64 · bookwormAffected
nvd · golang-github-xenolf-lego · debian · bookworm; nvd · golang-github-xenolf-lego · debian · 12
4.9.1-1· arm64 · bookwormAffected
nvd · golang-github-xenolf-lego · debian · bookworm; nvd · golang-github-xenolf-lego · debian · 12
[Debian 13 (Trixie)]
- [golang-github-xenolf-lego-dev]Affected
Source package: [golang-github-xenolf-lego]
Details (4)
4.9.1-2· all · trixieAffected
nvd · golang-github-xenolf-lego · debian · 13
4.9.1-2· all · trixieAffected
nvd · golang-github-xenolf-lego · debian · 13
4.35.2-3~bpo13+1· all · trixie-backportsAffected
nvd · golang-github-xenolf-lego · debian · 13
4.35.2-3~bpo13+1· all · trixie-backportsAffected
nvd · golang-github-xenolf-lego · debian · 13
- [lego]Affected
Source package: [golang-github-xenolf-lego]
Details (4)
4.9.1-2· amd64 · trixieAffected
nvd · golang-github-xenolf-lego · debian · 13
4.9.1-2· arm64 · trixieAffected
nvd · golang-github-xenolf-lego · debian · 13
4.35.2-3~bpo13+1· amd64 · trixie-backportsAffected
nvd · golang-github-xenolf-lego · debian · 13
4.35.2-3~bpo13+1· arm64 · trixie-backportsAffected
nvd · golang-github-xenolf-lego · debian · 13
Observed:
References
- [https://access.redhat.com/errata/RHSA-2026:21772]
- [https://access.redhat.com/security/cve/CVE-2026-40611]
- [https://bugzilla.redhat.com/show_bug.cgi?id=2460233]
- [https://github.com/go-acme/lego/security/advisories/GHSA-qqx8-2xmm-jrv8]
- [https://nvd.nist.gov/vuln/detail/CVE-2026-40611]
- [https://osv.dev/vulnerability/DEBIAN-CVE-2026-40611]
- [https://security-tracker.debian.org/tracker/CVE-2026-40611]
- [https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-40611.json]
[Debian Security Tracker] · [FIRST EPSS] · [National Vulnerability Database (NVD)] · [OSV Package Vulnerability Database] · [Red Hat security advisories and VEX]