Webmin HTTP header authentication bypass_CVE-2026-56020

8.1 / 10

HIGH

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H

Description

The Webmin HTTP server (miniserv.pl) allows unauthenticated attackers to impersonate any user with a configured SSL client certificate by sending a forged HTTP header. A remote attacker can spoof certificate DNs and authenticate as any user. Fixed in 2.641.

Basic Information

ID CVE-2026-56020

Source cisa-cg

Published Jun 18, 2026 at 16:12

Modified Jun 19, 2026 at 03:55

Affected Product

Vendor Webmin

Product Webmin

Affected Versions Webmin Webmin 0

CWE Classification

CWE-290

References

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    "lastseen": "",
    "description": "The Webmin HTTP server (miniserv.pl) allows unauthenticated attackers to impersonate any user with a configured SSL client certificate by sending a forged HTTP header. A remote attacker can spoof certificate DNs and authenticate as any user. Fixed in 2.641.",
    "published": "2026-06-18T16:12:05.368Z",
    "modified": "2026-06-19T03:55:49.972Z",
    "type": "cve",
    "title": "Webmin HTTP header authentication bypass",
    "source": "cisa-cg",
    "references": "https://github.com/webmin/webmin/releases/tag/2.641\nhttps://webmin.com/security/#webmin-prior-to-2641\nhttps://raw.githubusercontent.com/cisagov/CSAF/develop/csaf_files/IT/white/2026/va-26-169-02.json\nhttps://www.cve.org/CVERecord?id=CVE-2026-56020",
    "id": "CVE-2026-56020",
    "bulletinFamily": "",
    "cwe": [
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    "cvelist": null,
    "sourceData": "Webmin Webmin 0",
    "sourceHref": "",
    "cvss": {
        "score": 8.1,
        "severity": "HIGH",
        "vector": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H",
        "version": "3.1"
    },
    "cvss2": [],
    "cvss3": {
        "version": "",
        "vectorString": "",
        "baseScore": 0,
        "baseSeverity": "",
        "attackVector": "",
        "attackComplexity": "",
        "privilegesRequired": "",
        "userInteraction": "",
        "scope": "",
        "confidentialityImpact": "",
        "integrityImpact": "",
        "availabilityImpact": "",
        "cvssV3": {
            "version": "",
            "vectorString": "",
            "baseScore": 0,
            "baseSeverity": "",
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            "availabilityImpact": ""
        }
    },
    "href": "",
    "category_name": "CVE",
    "post_link": "",
    "product": "Webmin",
    "version": "0",
    "vendor": "Webmin",
    "ai_description": "",
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    "ai_score": 0
}