CVE-2026-40611
Fixed in a distro release EPSS <1%CVSS 8.8
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.
Products: go-acme lego, Red Hat OpenShift Dev Spaces 3.28
Fixed upstream
| Ecosystem | Package | Fixed in |
|---|---|---|
| Go | github.com/go-acme/lego | no fix |
| Go | github.com/go-acme/lego/v3 | no fix |
| Go | github.com/go-acme/lego/v4 | 4.34.0 |
Distro releases
| Release | Package | Fixed in |
|---|---|---|
| Chainguard | sftpgo | 2.7.1-r8 |
| Chainguard | traefik-2.11 | 2.11.44-r0 |
| Chainguard | traefik-3.6 | 3.6.13-r2 |
| Chainguard | traefik-fips-2.11 | 2.11.44-r0 |
| Chainguard | traefik-fips-3.5 | no fix |
| Chainguard | traefik-fips-3.6 | 3.6.13-r2 |
| Debian 12 | golang-github-xenolf-lego | no fix |
| Debian 13 | golang-github-xenolf-lego | no fix |
| Debian 14 | golang-github-xenolf-lego | 4.35.2-1 |
| SUSE Linux Enterprise Server 16.0 | govulncheck-vulndb | 0.0.20260727T201416-160000.1.1 |
| SUSE Linux Enterprise Server for SAP applications 16.0 | govulncheck-vulndb | 0.0.20260727T201416-160000.1.1 |
| Ubuntu 18.04 LTS | golang-github-xenolf-lego | no fix |
| Ubuntu 20.04 LTS | golang-github-xenolf-lego | no fix |
| Ubuntu 22.04 LTS | golang-github-xenolf-lego | no fix |
| Ubuntu 25.10 | golang-github-xenolf-lego | no fix |
| Ubuntu 26.04 LTS | golang-github-xenolf-lego | no fix |
| Ubuntu 26.10 | golang-github-xenolf-lego | no fix |
| Ubuntu Pro 24.04 LTS | golang-github-xenolf-lego | no fix |
| Wolfi | sftpgo | 2.7.1-r8 |
| Wolfi | traefik-3.6 | 3.6.13-r2 |
| openSUSE Leap 16.0 | govulncheck-vulndb | 0.0.20260727T201416-160000.1.1 |