# CVE-2026-126781: Webmin through 2.670 Users File Injection via acl/cert_issue.cgi

Status: published. Published: 2026-11-11. Updated: 2026-11-11.

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.

## Remediation

- fix: The reporting source identifies this reference as a patch. Check the advisory for affected versions and supported release branches. (source: CNA: VulnCheck) — https://github.com/webmin/webmin/commit/0c449e341746d8c445c8c7db223eac1f41755943
- fix: The reporting source identifies this reference as a patch. Check the advisory for affected versions and supported release branches. (source: CNA: VulnCheck) — https://github.com/webmin/webmin/commit/8fb194e5fbc30a6664545d48940d03759ace9bf2

## Affected products and versions

- webmin / webmin (webmin/webmin): ≥ 0; ≤ 2.670 (affected, custom). Source: CNA: VulnCheck

## Severity and prioritization

- CVSS 4.0: 7.7 (high); CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N; source: CNA: VulnCheck

- CVSS 3.1: 7.5 (high); CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H; source: CNA: VulnCheck

- CISA KEV: No listing in collected sources

- EPSS: Not available

- SSVC: Not available

- Weaknesses: CWE-93

## Exploit evidence

No exploit evidence in collected sources. This is not proof of no exploitation.

## References

- https://github.com/webmin/webmin/commit/0c449e341746d8c445c8c7db223eac1f41755943 (CNA: VulnCheck; patch)

- https://github.com/webmin/webmin/commit/8fb194e5fbc30a6664545d48940d03759ace9bf2 (CNA: VulnCheck; patch)

- https://github.com/webmin/webmin/blob/2.670/acl/cert_issue.cgi#L22-L52 (CNA: VulnCheck; technical-description)

- https://www.vulncheck.com/advisories/webmin-through-2.670-users-file-injection-via-acl-cert-issue-cgi (CNA: VulnCheck; third-party-advisory)

## Provenance

- CNA: VulnCheck: https://www.cve.org/CVERecord?id=CVE-2026-126781; retrieved 2026-11-11; source updated 2026-11-11

Revision: 5ed486b2741c3f4d632dc663d30ed779bde0c72d74eae190d06ea80a5bb655b6

Canonical: https://y2.dev/cve/CVE-2026-126781

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