Vulnerability-Lookup

GHSA-G4FX-R8M5-C6R7

Vulnerability from github – Published: 2026-10-15 06:30 – Updated: 2026-10-15 06:30

Details

In Znuny through 7.3.6, an attacker can bypass specific standard login procedures and gain unauthorized access to sensitive system functions by manipulating a specific HTTP request header. Because the application incorrectly trusts this header, an attacker can impersonate any user, including administrators, without requiring a password. This grants full access to confidential data and system controls. More specifically, the HTTPBasicAuth modules for the agent (Kernel::System::Auth::HTTPBasicAuth) and customer (Kernel::System::CustomerAuth::HTTPBasicAuth) interfaces read the username to log in not only from $ENV{REMOTE_USER} (set by the web server after successful authentication), but also, as a fallback, from $ENV{HTTP_REMOTE_USER}, which is populated directly from an attacker-controllable "Remote-User" request header. On systems where HTTPBasicAuth was configured as the authentication backend, this allowed an attacker to log in as any existing user by sending a request with a forged Remote-User header, without providing any credentials.

Severity

9.5 (Critical)


                  
                    CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:L/SC:H/SI:H/SA:L/AU:Y/R:U/RE:L/U:Red

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{
  "affected": [],
  "aliases": [
    "CVE-2026-93483"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-348"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-10-15T04:18:30Z",
    "severity": "CRITICAL"
  },
  "details": "In Znuny through 7.3.6, an attacker can bypass specific standard login procedures and gain unauthorized access to sensitive system functions by manipulating a specific HTTP request header. Because the application incorrectly trusts this header, an attacker can impersonate any user, including administrators, without requiring a password. This grants full access to confidential data and system controls. More specifically, the HTTPBasicAuth modules for the agent (Kernel::System::Auth::HTTPBasicAuth) and customer (Kernel::System::CustomerAuth::HTTPBasicAuth) interfaces read the username to log in not only from $ENV{REMOTE_USER} (set by the web server after successful authentication), but also, as a fallback, from $ENV{HTTP_REMOTE_USER}, which is populated directly from an attacker-controllable \"Remote-User\" request header. On systems where HTTPBasicAuth was configured as the authentication backend, this allowed an attacker to log in as any existing user by sending a request with a forged Remote-User header, without providing any credentials.",
  "id": "GHSA-g4fx-r8m5-c6r7",
  "modified": "2026-10-15T06:30:43Z",
  "published": "2026-10-15T06:30:43Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-93483"
    },
    {
      "type": "WEB",
      "url": "https://www.znuny.org/advisories"
    },
    {
      "type": "WEB",
      "url": "https://www.znuny.org/en/advisories/zsa-2026-14"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:L/SC:H/SI:H/SA:L/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:Y/R:U/V:X/RE:L/U:Red",
      "type": "CVSS_V4"
    }
  ]
}

CVE-2026-93483 (GCVE-0-2026-93483)

Vulnerability from cvelistv5 – Published: 2026-10-15 03:43 – Updated: 2026-10-15 03:43

Summary

Severity

9.5 (Critical)


                        
                          CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:L/SC:H/SI:H/SA:L/AU:Y/R:U/RE:L/U:Red

CWE

CWE-348 - Use of Less Trusted Source

Assigner

mitre CNA under the mitre root

CNA scorecard E 28/100 over 2325 records in the last 180 days details

References

2 references

URL	Tags
https://www.znuny.org/advisories
https://www.znuny.org/en/advisories/zsa-2026-14

Impacted products

1 product

Vendor	Product	Version
Znuny	Znuny	Affected: 0 , < 6.5.25 (semver) Affected: 7.0.0 , < 7.3.7 (semver) cpe:2.3:a:znuny:znuny:::::::: cpe:2.3:a:znuny:znuny::::::::

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JSON

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{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Znuny",
          "repo": "https://github.com/znuny/znuny",
          "vendor": "Znuny",
          "versions": [
            {
              "lessThan": "6.5.25",
              "status": "affected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThan": "7.3.7",
              "status": "affected",
              "version": "7.0.0",
              "versionType": "semver"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:a:znuny:znuny:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.5.25",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:a:znuny:znuny:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.3.7",
                  "versionStartIncluding": "7.0.0",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In Znuny through 7.3.6, an attacker can bypass specific standard login procedures and gain unauthorized access to sensitive system functions by manipulating a specific HTTP request header. Because the application incorrectly trusts this header, an attacker can impersonate any user, including administrators, without requiring a password. This grants full access to confidential data and system controls. More specifically, the HTTPBasicAuth modules for the agent (Kernel::System::Auth::HTTPBasicAuth) and customer (Kernel::System::CustomerAuth::HTTPBasicAuth) interfaces read the username to log in not only from $ENV{REMOTE_USER} (set by the web server after successful authentication), but also, as a fallback, from $ENV{HTTP_REMOTE_USER}, which is populated directly from an attacker-controllable \"Remote-User\" request header. On systems where HTTPBasicAuth was configured as the authentication backend, this allowed an attacker to log in as any existing user by sending a request with a forged Remote-User header, without providing any credentials."
        }
      ],
      "metrics": [
        {
          "cvssV4_0": {
            "Automatable": "YES",
            "Recovery": "USER",
            "Safety": "NOT_DEFINED",
            "attackComplexity": "LOW",
            "attackRequirements": "PRESENT",
            "attackVector": "NETWORK",
            "baseScore": 9.5,
            "baseSeverity": "CRITICAL",
            "privilegesRequired": "NONE",
            "providerUrgency": "RED",
            "subAvailabilityImpact": "LOW",
            "subConfidentialityImpact": "HIGH",
            "subIntegrityImpact": "HIGH",
            "userInteraction": "NONE",
            "valueDensity": "NOT_DEFINED",
            "vectorString": "CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:L/SC:H/SI:H/SA:L/AU:Y/R:U/RE:L/U:Red",
            "version": "4.0",
            "vulnAvailabilityImpact": "LOW",
            "vulnConfidentialityImpact": "HIGH",
            "vulnIntegrityImpact": "HIGH",
            "vulnerabilityResponseEffort": "LOW"
          },
          "format": "CVSS",
          "scenarios": [
            {
              "lang": "en",
              "value": "GENERAL"
            }
          ]
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "cweId": "CWE-348",
              "description": "CWE-348 Use of Less Trusted Source",
              "lang": "en",
              "type": "CWE"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-10-15T03:43:10.406Z",
        "orgId": "8254265b-2729-46b6-b9e3-3dfca2d5bfca",
        "shortName": "mitre"
      },
      "references": [
        {
          "url": "https://www.znuny.org/advisories"
        },
        {
          "url": "https://www.znuny.org/en/advisories/zsa-2026-14"
        }
      ],
      "x_generator": {
        "engine": "CVE-Request-form 0.0.1"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "8254265b-2729-46b6-b9e3-3dfca2d5bfca",
    "assignerShortName": "mitre",
    "cveId": "CVE-2026-93483",
    "datePublished": "2026-10-15T03:43:10.406Z",
    "dateReserved": "2026-09-18T04:33:42.990Z",
    "dateUpdated": "2026-10-15T03:43:10.406Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}

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.

Vulnerability timeline

Sightings and recorded dates, grouped by day · UTC

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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.

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