GHSA-g7hg-vrcf-mvmr: Netty: Out-of-date OCSP Responses Accepted by OcspServerCertificateValidator

Summary OcspServerCertificateValidator flags an out-of-date OCSP response but does not stop processing it, so an expired GOOD response is still reported as VALID, letting an on-path attacker replay a stale GOOD response to bypass revocation of a since-revoked certificate. Details In io.netty.handler.ssl.ocsp.OcspServerCertificateValidator#userEventTriggered the freshness check has no return, so execution falls through and a VALID OcspValidationEvent is still fired: if (!(current.after(response.getThisUpdate()) && current.before(response.getNextUpdate()))) { ctx.fireExceptionCaught(new IllegalStateException("OCSP Response is out-of-date")); } Nonce validation is optional and off by default, so freshness is the only replay defense — and it is not enforced. Additionally getNextUpdate() may be null, making current.before(null) throw NullPointerException. https://datatracker.ietf.org/doc/html/rfc6960#section-3.2 5. The time at which the status being indicated is known to be correct (thisUpdate) is sufficiently recent; 6. When available, the time at or before which newer information will be available about the status of the certificate (nextUpdate) is greater than the current time. PoC Add the test below to io.netty.handler.ssl.ocsp.OcspServerCertificateValidatorTest @Test void staleOcspResponseIsRejected() throws Exception { X509Bundle caRoot = new CertificateBuilder() .algorithm(CertificateBuilder.Algorithm.rsa2048) .subject("CN=TrustedRootCA") .setIsCertificateAuthority(true) .buildSelfSigned(); GeneralName ocspName = new GeneralName(GeneralName.uniformResourceIdentifier, "http://localhost/"); AuthorityInformationAccess aia = new AuthorityInformationAccess( new AccessDescription(AccessDescription.id_ad_ocsp, ocspName)); X509Bundle targetCert = new CertificateBuilder() .algorithm(CertificateBuilder.Algorithm.rsa2048) .subject("CN=TargetServer") .addExtensionOctetString("1.3.6.1.5.5.7.1.1", false, aia.getEncoded()) .buildIssuedBy(caRoot); Date past = new Date(