CVE-2026-75759
Improper Verification of Cryptographic Signature vulnerability in erlef oidcc allows an unauthenticated attacker to impersonate an arbitrary user via an encrypted ID token or JARM response carrying…
Overview
CVE-2026-75759 is a known-severity vulnerability. It was published on August 30, 2026.
Technical description
Improper Verification of Cryptographic Signature vulnerability in erlef oidcc allows an unauthenticated attacker to impersonate an arbitrary user via an encrypted ID token or JARM response carrying no nested signature. OpenID Connect Core 1.0 section 2 requires that an encrypted ID token be signed then encrypted, with the result being a Nested JWT, and JARM processing rule 5 requires the client to check the signature unconditionally. oidcc instead accepted a JWE wrapping unsigned claims as fully validated, so anyone holding the relying party's public encryption key could mint a token with an arbitrary sub, iss, and aud without possessing the provider's signing key.
In oidcc_jwt_util:verify_decrypted_token/4, a decrypted payload that is not a signed JWS fell back to parsing the plaintext claims and returning them with no verifying key. oidcc_token:int_validate_jwt/4 then matched on the JOSE structure type rather than on whether a signature had been verified, and returned success. The J
Remediation
Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.
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Frequently asked questions
What is CVE-2026-75759?
CVE-2026-75759 is a known-severity vulnerability. It was published on August 30, 2026.
How severe is CVE-2026-75759?
CVSS score information is not yet available for this vulnerability. Check back as the CVE record is updated by NVD analysts.
How do I fix or remediate CVE-2026-75759?
Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.
How can CyberStrike help with CVE-2026-75759?
CyberStrike is an open-source, AI-augmented pentesting engine. Rather than flag a version number, it tests whether an issue like CVE-2026-75759 is actually reachable in your own applications and APIs, then verifies each finding before reporting it. That tells you if the weakness is a real, exploitable risk in your environment or a false positive you can safely deprioritize.