Vulnerability-Lookup

CVE-2026-56020 (GCVE-0-2026-56020)

Vulnerability from cvelistv5 – Published: 2026-06-18 16:12 – Updated: 2026-08-11 15:33

Title

Webmin HTTP header authentication bypass

Summary

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 2.202.

Severity

8.1 (High)


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

9.2 (Critical)


                        
                          CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N

SSVC

Exploitation: none Automatable: no Technical Impact: total

CISA Coordinator · cisa-cg (v2.0.3)

Decision recorded 2026-05-29 20:04 UTC

CWE

CWE-290 - Authentication Bypass by Spoofing

Assigner

cisa-cg CISA root

References

4 references

URL	Tags
https://github.com/webmin/webmin/releases/tag/2.202	release-notes
https://webmin.com/security/#webmin-prior-to-2202	release-notes
https://raw.githubusercontent.com/cisagov/CSAF/de…
https://www.cve.org/CVERecord?id=CVE-2026-56020	vdb-entry

Impacted products

1 product

Vendor	Product	Version	CPE status
Webmin	Webmin	Affected: 0 , < 2.202 (custom) Unaffected: 2.202	guessed

Date Public

2026-06-18 00:00

Credits

Adem El Adeb, vulone.com/vul1.com

Show details on NVD website

JSON

To clipboard

{
  "containers": {
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                "id": "CVE-2026-56020",
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}

FKIE_CVE-2026-56020

Vulnerability from fkie_nvd - Published: 2026-06-18 17:16 - Updated: 2026-08-11 16:17

Severity

8.1 (High) - CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H

Summary

References

	URL	Tags
	9119a7d8-5eab-497f-8521-727c672e3725	https://github.com/webmin/webmin/releases/tag/2.202
	9119a7d8-5eab-497f-8521-727c672e3725	https://raw.githubusercontent.com/cisagov/CSAF/develop/csaf_files/IT/white/2026/va-26-169-02.json
	9119a7d8-5eab-497f-8521-727c672e3725	https://webmin.com/security/#webmin-prior-to-2202
	9119a7d8-5eab-497f-8521-727c672e3725	https://www.cve.org/CVERecord?id=CVE-2026-56020

Impacted products

	Vendor	Product	Version

JSON

To clipboard

{
  "affected": [
    {
      "affectedData": [
        {
          "defaultStatus": "unknown",
          "product": "Webmin",
          "vendor": "Webmin",
          "versions": [
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    }
  ],
  "id": "CVE-2026-56020",
  "lastModified": "2026-08-11T16:17:33.077",
  "metrics": {
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          "confidentialityImpact": "HIGH",
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    ],
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          "baseSeverity": "CRITICAL",
          "confidentialityRequirement": "NOT_DEFINED",
          "exploitMaturity": "NOT_DEFINED",
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          "modifiedAttackComplexity": "NOT_DEFINED",
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          "modifiedAttackVector": "NOT_DEFINED",
          "modifiedPrivilegesRequired": "NOT_DEFINED",
          "modifiedSubAvailabilityImpact": "NOT_DEFINED",
          "modifiedSubConfidentialityImpact": "NOT_DEFINED",
          "modifiedSubIntegrityImpact": "NOT_DEFINED",
          "modifiedUserInteraction": "NOT_DEFINED",
          "modifiedVulnAvailabilityImpact": "NOT_DEFINED",
          "modifiedVulnConfidentialityImpact": "NOT_DEFINED",
          "modifiedVulnIntegrityImpact": "NOT_DEFINED",
          "privilegesRequired": "NONE",
          "providerUrgency": "NOT_DEFINED",
          "subAvailabilityImpact": "NONE",
          "subConfidentialityImpact": "NONE",
          "subIntegrityImpact": "NONE",
          "userInteraction": "NONE",
          "valueDensity": "NOT_DEFINED",
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        "type": "Secondary"
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    ],
    "ssvcV203": [
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        "ssvcData": {
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          "options": [
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          ],
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  "sourceIdentifier": "9119a7d8-5eab-497f-8521-727c672e3725",
  "vulnStatus": "Awaiting Analysis",
  "weaknesses": [
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      "description": [
        {
          "lang": "en",
          "value": "CWE-290"
        }
      ],
      "source": "9119a7d8-5eab-497f-8521-727c672e3725",
      "type": "Secondary"
    }
  ]
}

GHSA-23XJ-GFH3-WF2H

Vulnerability from github – Published: 2026-06-18 18:35 – Updated: 2026-08-11 18:30

Details

Severity

8.1 (High)


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

9.2 (Critical)


                  
                    CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N

Show details on source website

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{
  "affected": [],
  "aliases": [
    "CVE-2026-56020"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-290"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-06-18T17:16:35Z",
    "severity": "CRITICAL"
  },
  "details": "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.",
  "id": "GHSA-23xj-gfh3-wf2h",
  "modified": "2026-08-11T18:30:35Z",
  "published": "2026-06-18T18:35:24Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-56020"
    },
    {
      "type": "WEB",
      "url": "https://github.com/webmin/webmin/releases/tag/2.202"
    },
    {
      "type": "WEB",
      "url": "https://github.com/webmin/webmin/releases/tag/2.641"
    },
    {
      "type": "WEB",
      "url": "https://raw.githubusercontent.com/cisagov/CSAF/develop/csaf_files/IT/white/2026/va-26-169-02.json"
    },
    {
      "type": "WEB",
      "url": "https://webmin.com/security/#webmin-prior-to-2202"
    },
    {
      "type": "WEB",
      "url": "https://webmin.com/security/#webmin-prior-to-2641"
    },
    {
      "type": "WEB",
      "url": "https://www.cve.org/CVERecord?id=CVE-2026-56020"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H",
      "type": "CVSS_V3"
    },
    {
      "score": "CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X",
      "type": "CVSS_V4"
    }
  ]
}

VA-26-169-02

Vulnerability from csaf_cisa - Published: 2026-06-18 15:56 - Updated: 2026-08-11 15:32

Summary

Webmin multiple vulnerabilities

Scope

3 vulnerabilities in this advisory, including CVE-2026-56020.

CVE-2026-56020

8.1 (High)


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

Known affected: 1 product Fixed: 1 product

Open the full advisory

Sightings

Author	Source	Type	Date	Other

Nomenclature

Seen: The vulnerability was mentioned, discussed, or observed by the user.
Confirmed: The vulnerability has been validated from an analyst's perspective.
Published Proof of Concept: A public proof of concept is available for this vulnerability.
Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
Not confirmed: The user expressed doubt about the validity of the vulnerability.
Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.

Detection rules are retrieved from Rulezet.

The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base model, served locally by ML-Gateway. They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
Browse all ATT&CK techniques and the vulnerabilities related to each.

Related by attack behaviour

Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.

Action not permitted

CVE-2026-56020 (GCVE-0-2026-56020)

FKIE_CVE-2026-56020

GHSA-23XJ-GFH3-WF2H

VA-26-169-02

Tags

Sightings

Nomenclature

Related by attack behaviour