Summary
Apple App Store Server Python Library: SignedDataVerifier accepts stale OCSP GOOD responses and can bypass certificate revocation checks
Advisory details
Summary
SignedDataVerifier attempts to perform online revocation checking when enable_online_checks=True, but its OCSP validation logic accepts stale GOOD responses as valid indefinitely. In appstoreserverlibrary/signed_data_verifier.py, _ChainVerifier.check_ocsp_status() verifies the OCSP response signature and CertID match, but never validates the freshness window carried by producedAt, thisUpdate, or nextUpdate.
As a result, a previously valid signed OCSP GOOD response can be replayed after it is expired, and the library will still treat the certificate as good. If an App Store signing certificate or intermediate is ever revoked, applications using this library with online checks enabled can continue accepting JWS objects signed with the revoked key as long as a stale signed OCSP response is replayed.
References
Related vulnerabilities
All Supply chain →- HIGHCVE-2026-55215
MariaDB's connector leaks the cleartext password to an MitM despite `ssl: true`
- MEDIUMCVE-2026-63336
RabbitMQ Java client: TrustEverythingTrustManager used by default in useSslProtocol() enables MITM
- MEDIUMCVE-2026-69248
python-cryptography verifier accepts wildcard DNS names allowing escape from permittedSubtrees
- CRITICALCVE-2026-46428
lettre has TLS hostname verification disabled when using Boring TLS backend
- HIGHCVE-2026-56821
Netty: Out-of-date OCSP Responses Accepted by OcspServerCertificateValidator
- HIGHCVE-2026-56820
Netty: Missing CertificateID Validation in OCSP Response Allows Replay Attacks