---
id: "CVE-2026-126781"
page: "https://infrastack.ai/live/CVE-2026-126781"
kind: "vulnerability"
aliases: ["CVE-2026-126781"]
title: "Webmin: certificate form lets logged-in users inject root account entries"
severity: "high"
cvss: 7.7
epss: null
exploited: false
status: "open"
category: "other"
products: []
ecosystems: []
tags: ["linux", "other", "self-hosted", "webmin"]
not_affected_if: ["no-webmin", "webmin-login-restricted-to-admins"]
published_at: "2026-11-11T19:17:39+00:00"
first_seen_at: "2026-11-11T19:28:47+00:00"
updated_at: "2026-11-11T19:30:00+00:00"
sources: [{"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-126781", "first_seen_at": "2026-11-11T19:28:47+00:00"}]
exploit_sources: []
---

# Webmin: certificate form lets logged-in users inject root account entries

Link for people: https://infrastack.ai/live/CVE-2026-126781 (this .md is for agents)

Webmin through version 2.670 does not validate certificate DN fields in acl/cert_issue.cgi, so newline characters can be written into the Webmin users file. An authenticated user can add a second root entry with a known password hash and gain full Webmin root access after miniserv restarts.

_Summary, check and fix written by a model from the sources; labelled as such._

## How to check

- Check the installed Webmin version (`webmin --version` or the version shown in the Webmin UI) and compare it with the fixed release in the sources.
- Review which Webmin accounts exist and whether any unexpected root-level entries appear in the Webmin users file.

## Fix

- Webmin: unknown (the sources give patch links on github.com but do not state the fixed version number in the provided text)

## Timeline

- 2026-11-11T19:28:47+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2026-126781

## Documents

- [advisory] Third-party advisory: www.vulncheck.com https://www.vulncheck.com/advisories/webmin-through-2.670-users-file-injection-via-acl-cert-issue-cgi
- [fix] Patch: github.com https://github.com/webmin/webmin/commit/0c449e341746d8c445c8c7db223eac1f41755943
- [fix] Patch: github.com https://github.com/webmin/webmin/commit/8fb194e5fbc30a6664545d48940d03759ace9bf2

## From the sources

Webmin through 2.670 contains a users file injection vulnerability in acl/cert_issue.cgi that allows authenticated Webmin users to inject lines by supplying unvalidated certificate DN fields containing newlines. Attackers can end a DN field with a backslash and newline to add a second root entry with a known password hash, gaining Webmin root access after miniserv restarts.

---

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