CVE-2026-43924 (GCVE-0-2026-43924)

Vulnerability from cvelistv5 – Published: 2026-06-03 19:56 – Updated: 2026-06-03 19:56
VLAI
Title
FOSSBilling has an open redirect via administrator-configured redirect targets
Summary
FOSSBilling is a free, open-source billing and client management system. Prior to version 0.8.0, the Redirect module does not validate the URL scheme of administrator-configured destination URLs before storing or issuing redirects. This allows arbitrary external URLs to be configured as redirect targets, creating an open redirect vulnerability exploitable for phishing attacks. Users following a legitimate FOSSBilling URL can be silently redirected to an attacker-controlled external site. The redirect is issued as a 301 (Moved Permanently) response, which browsers cache persistently, amplifying the impact. Exploitation requires administrator privileges to create or modify redirect entries, limiting practical attack scenarios to multi-admin environments or compromised admin accounts. Version 0.8.0 fixes the issue. Some workarounds are available. Restrict admin access to the Redirect module to trusted administrators only and/or audit existing redirect entries in the database (the `extension_meta` table with `extension = 'mod_redirect'`) for any unexpected or external target URLs.
Severity
4.8 (Medium)
CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:P/VC:N/VI:N/VA:N/SC:N/SI:L/SA:N
CWE
  • CWE-601 - URL Redirection to Untrusted Site ('Open Redirect')
Assigner
References
Impacted products
Vendor Product Version
FOSSBilling FOSSBilling Affected: < 0.8.0
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{
  "containers": {
    "cna": {
      "affected": [
        {
          "product": "FOSSBilling",
          "vendor": "FOSSBilling",
          "versions": [
            {
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              "version": "\u003c 0.8.0"
            }
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        }
      ],
      "descriptions": [
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          "value": "FOSSBilling is a free, open-source billing and client management system. Prior to version 0.8.0, the Redirect module does not validate the URL scheme of administrator-configured destination URLs before storing or issuing redirects. This allows arbitrary external URLs to be configured as redirect targets, creating an open redirect vulnerability exploitable for phishing attacks. Users following a legitimate FOSSBilling URL can be silently redirected to an attacker-controlled external site. The redirect is issued as a 301 (Moved Permanently) response, which browsers cache persistently, amplifying the impact. Exploitation requires administrator privileges to create or modify redirect entries, limiting practical attack scenarios to multi-admin environments or compromised admin accounts. Version 0.8.0 fixes the issue. Some workarounds are available. Restrict admin access to the Redirect module to trusted administrators only and/or audit existing redirect entries in the database (the `extension_meta` table with `extension = \u0027mod_redirect\u0027`) for any unexpected or external target URLs."
        }
      ],
      "metrics": [
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            "attackRequirements": "NONE",
            "attackVector": "NETWORK",
            "baseScore": 4.8,
            "baseSeverity": "MEDIUM",
            "privilegesRequired": "HIGH",
            "subAvailabilityImpact": "NONE",
            "subConfidentialityImpact": "NONE",
            "subIntegrityImpact": "LOW",
            "userInteraction": "PASSIVE",
            "vectorString": "CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:P/VC:N/VI:N/VA:N/SC:N/SI:L/SA:N",
            "version": "4.0",
            "vulnAvailabilityImpact": "NONE",
            "vulnConfidentialityImpact": "NONE",
            "vulnIntegrityImpact": "NONE"
          }
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "cweId": "CWE-601",
              "description": "CWE-601: URL Redirection to Untrusted Site (\u0027Open Redirect\u0027)",
              "lang": "en",
              "type": "CWE"
            }
          ]
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      ],
      "providerMetadata": {
        "dateUpdated": "2026-06-03T19:56:25.836Z",
        "orgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
        "shortName": "GitHub_M"
      },
      "references": [
        {
          "name": "https://github.com/FOSSBilling/FOSSBilling/security/advisories/GHSA-v8rf-g37v-vgpx",
          "tags": [
            "x_refsource_CONFIRM"
          ],
          "url": "https://github.com/FOSSBilling/FOSSBilling/security/advisories/GHSA-v8rf-g37v-vgpx"
        },
        {
          "name": "https://github.com/FOSSBilling/FOSSBilling/releases/tag/0.8.0",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/FOSSBilling/FOSSBilling/releases/tag/0.8.0"
        }
      ],
      "source": {
        "advisory": "GHSA-v8rf-g37v-vgpx",
        "discovery": "UNKNOWN"
      },
      "title": "FOSSBilling has an open redirect via administrator-configured redirect targets"
    }
  },
  "cveMetadata": {
    "assignerOrgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
    "assignerShortName": "GitHub_M",
    "cveId": "CVE-2026-43924",
    "datePublished": "2026-06-03T19:56:25.836Z",
    "dateReserved": "2026-05-04T16:59:09.089Z",
    "dateUpdated": "2026-06-03T19:56:25.836Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2",
  "vulnerability-lookup:meta": {
    "nvd": "{\"cve\":{\"id\":\"CVE-2026-43924\",\"sourceIdentifier\":\"security-advisories@github.com\",\"published\":\"2026-06-03T20:16:21.133\",\"lastModified\":\"2026-06-03T20:16:21.133\",\"vulnStatus\":\"Received\",\"cveTags\":[],\"descriptions\":[{\"lang\":\"en\",\"value\":\"FOSSBilling is a free, open-source billing and client management system. Prior to version 0.8.0, the Redirect module does not validate the URL scheme of administrator-configured destination URLs before storing or issuing redirects. This allows arbitrary external URLs to be configured as redirect targets, creating an open redirect vulnerability exploitable for phishing attacks. Users following a legitimate FOSSBilling URL can be silently redirected to an attacker-controlled external site. The redirect is issued as a 301 (Moved Permanently) response, which browsers cache persistently, amplifying the impact. Exploitation requires administrator privileges to create or modify redirect entries, limiting practical attack scenarios to multi-admin environments or compromised admin accounts. Version 0.8.0 fixes the issue. Some workarounds are available. Restrict admin access to the Redirect module to trusted administrators only and/or audit existing redirect entries in the database (the `extension_meta` table with `extension = \u0027mod_redirect\u0027`) for any unexpected or external target URLs.\"}],\"metrics\":{\"cvssMetricV40\":[{\"source\":\"security-advisories@github.com\",\"type\":\"Secondary\",\"cvssData\":{\"version\":\"4.0\",\"vectorString\":\"CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:P/VC:N/VI:N/VA:N/SC:N/SI:L/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\",\"baseScore\":4.8,\"baseSeverity\":\"MEDIUM\",\"attackVector\":\"NETWORK\",\"attackComplexity\":\"LOW\",\"attackRequirements\":\"NONE\",\"privilegesRequired\":\"HIGH\",\"userInteraction\":\"PASSIVE\",\"vulnConfidentialityImpact\":\"NONE\",\"vulnIntegrityImpact\":\"NONE\",\"vulnAvailabilityImpact\":\"NONE\",\"subConfidentialityImpact\":\"NONE\",\"subIntegrityImpact\":\"LOW\",\"subAvailabilityImpact\":\"NONE\",\"exploitMaturity\":\"NOT_DEFINED\",\"confidentialityRequirement\":\"NOT_DEFINED\",\"integrityRequirement\":\"NOT_DEFINED\",\"availabilityRequirement\":\"NOT_DEFINED\",\"modifiedAttackVector\":\"NOT_DEFINED\",\"modifiedAttackComplexity\":\"NOT_DEFINED\",\"modifiedAttackRequirements\":\"NOT_DEFINED\",\"modifiedPrivilegesRequired\":\"NOT_DEFINED\",\"modifiedUserInteraction\":\"NOT_DEFINED\",\"modifiedVulnConfidentialityImpact\":\"NOT_DEFINED\",\"modifiedVulnIntegrityImpact\":\"NOT_DEFINED\",\"modifiedVulnAvailabilityImpact\":\"NOT_DEFINED\",\"modifiedSubConfidentialityImpact\":\"NOT_DEFINED\",\"modifiedSubIntegrityImpact\":\"NOT_DEFINED\",\"modifiedSubAvailabilityImpact\":\"NOT_DEFINED\",\"Safety\":\"NOT_DEFINED\",\"Automatable\":\"NOT_DEFINED\",\"Recovery\":\"NOT_DEFINED\",\"valueDensity\":\"NOT_DEFINED\",\"vulnerabilityResponseEffort\":\"NOT_DEFINED\",\"providerUrgency\":\"NOT_DEFINED\"}}]},\"weaknesses\":[{\"source\":\"security-advisories@github.com\",\"type\":\"Primary\",\"description\":[{\"lang\":\"en\",\"value\":\"CWE-601\"}]}],\"references\":[{\"url\":\"https://github.com/FOSSBilling/FOSSBilling/releases/tag/0.8.0\",\"source\":\"security-advisories@github.com\"},{\"url\":\"https://github.com/FOSSBilling/FOSSBilling/security/advisories/GHSA-v8rf-g37v-vgpx\",\"source\":\"security-advisories@github.com\"}]}}"
  }
}


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Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

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