cvedb.io
CVE-2026-40611
HIGH · CVSS 8.8
EPSS exploitation probability: 0%
Published 2026-04-21T18:16:52.457 · Last modified 2026-06-30T03:19:19.460

Summary

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.

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References

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