CVE-2026-71891

In Bouncy Castle for Java before 1.86, BLS12381BasicScheme.keyValidate, and so BLSPublicKeyParameters and every BasicScheme, MessageAugmentation and ProofOfPossession verify and aggregateVerify that gate on it, accepted a public key built on a foreign ECCurve that merely shares BLS12-381's field...

UBUNTU-CVE-2026-18040

In Bouncy Castle for Java before 1.86, HQC leaked secret-derived data through two side channels: its GF2^8 arithmetic used lookup tables indexed by field elements, making the cache line touched a function of the operand, and its fixed-weight support sampler left its duplicate scan as soon as a...

UBUNTU-CVE-2026-71885

In Bouncy Castle for Java before 1.86, the Messaging Layer Security MLS, RFC 9420 implementation did not bind an X.509 credential to a LeafNode's signaturekey. LeafNode.verify checked a leaf's signature against the signaturekey carried in the leaf itself, while the credential's X.509 certificate...

UBUNTU-CVE-2026-71886

In Bouncy Castle for Java before 1.86, the high-level OpenPGP certificate API accepted a third-party certification or trust delegation from any component key of the issuing certificate, without requiring that component to have been granted the authority to certify...

UBUNTU-CVE-2026-71891

In Bouncy Castle for Java before 1.86, BLS12381BasicScheme.keyValidate, and so BLSPublicKeyParameters and every BasicScheme, MessageAugmentation and ProofOfPossession verify and aggregateVerify that gate on it, accepted a public key built on a foreign ECCurve that merely shares BLS12-381's field...

UBUNTU-CVE-2026-71892

In Bouncy Castle for Java before 1.86, the opt-in key-size validation on CMS key-transport recipients, org.bouncycastle.cms.jcajce.JceKeyTransRecipient.setKeySizeValidationtrue, never ran for a message using RFC 9709 content-encryption key derivation id-alg-cek-hkdf-sha256. The branch that should...

CVE-2026-71886

In Bouncy Castle for Java before 1.86, the high-level OpenPGP certificate API accepted a third-party certification or trust delegation from any component key of the issuing certificate, without requiring that component to have been granted the authority to certify...

CVE-2026-71888

In Bouncy Castle for Java before 1.86, the streaming CMS AuthenticatedData parser accepted a message whose digestAlgorithm and authAttrs fields disagreed about whether authenticated attributes were present. RFC 5652 sec. 9.1 pairs the two, requiring that authAttrs be present whenever...

CVE-2026-71889

In Bouncy Castle for Java before 1.86, neither copy of PKIXCertPathReviewer - org.bouncycastle.pkix.jcajce.PKIXCertPathReviewer nor the legacy org.bouncycastle.x509.PKIXCertPathReviewer - applied X.509 name constraints to the end-entity certificate. checkNameConstraints walked the path with a loo...

CVE-2026-71892

In Bouncy Castle for Java before 1.86, the opt-in key-size validation on CMS key-transport recipients, org.bouncycastle.cms.jcajce.JceKeyTransRecipient.setKeySizeValidationtrue, never ran for a message using RFC 9709 content-encryption key derivation id-alg-cek-hkdf-sha256. The branch that should...

CVE-2026-85515

In Bouncy Castle for Java before 1.86, a truncated OpenPGP encrypted message was accepted with no error reported, and on the SEIPD version 1 path with no integrity check performed at all. RFC 9580 sec. 13.7 permits an implementation to release the cleartext of the fully authenticated chunks when...

UBUNTU-CVE-2026-71888

In Bouncy Castle for Java before 1.86, the streaming CMS AuthenticatedData parser accepted a message whose digestAlgorithm and authAttrs fields disagreed about whether authenticated attributes were present. RFC 5652 sec. 9.1 pairs the two, requiring that authAttrs be present whenever...

UBUNTU-CVE-2026-71889

In Bouncy Castle for Java before 1.86, neither copy of PKIXCertPathReviewer - org.bouncycastle.pkix.jcajce.PKIXCertPathReviewer nor the legacy org.bouncycastle.x509.PKIXCertPathReviewer - applied X.509 name constraints to the end-entity certificate. checkNameConstraints walked the path with a loo...

UBUNTU-CVE-2026-71890

In Bouncy Castle for Java before 1.86, validation of an MLS RFC 9420 external commit's proposal list, org.bouncycastle.mls.protocol.Group.validateExternalCachedProposals, counted the proposals by type and bounded the removed leaf index but never established that the removed leaf had anything to d...

UBUNTU-CVE-2026-85515

In Bouncy Castle for Java before 1.86, a truncated OpenPGP encrypted message was accepted with no error reported, and on the SEIPD version 1 path with no integrity check performed at all. RFC 9580 sec. 13.7 permits an implementation to release the cleartext of the fully authenticated chunks when...

UBUNTU-CVE-2026-71887

In Bouncy Castle for Java before 1.86, the high-level OpenPGP API accepted a data signature made by a signing subkey whose Subkey Binding signature carried no embedded Primary Key Binding cross-certification signature, in the case where that binding omits a Key Flags subpacket. RFC 9580 sec...

CVE-2026-71890 MLS external commit can remove an arbitrary group member

In Bouncy Castle for Java before 1.86, validation of an MLS RFC 9420 external commit's proposal list, org.bouncycastle.mls.protocol.Group.validateExternalCachedProposals, counted the proposals by type and bounded the removed leaf index but never established that the removed leaf had anything to d...

CVE-2026-71890

Bouncy Castle for Java versions before 1.86 are vulnerable to an authorization flaw in the MLS (RFC 9420) protocol implementation. The org.bouncycastle.mls.protocol.Group.validateExternalCachedProposals method fails to verify that a Remove proposal in an external commit belongs to the joiner. Thi...

CVE-2026-71890

In Bouncy Castle for Java before 1.86, validation of an MLS RFC 9420 external commit's proposal list, org.bouncycastle.mls.protocol.Group.validateExternalCachedProposals, counted the proposals by type and bounded the removed leaf index but never established that the removed leaf had anything to d...

EUVD-2026-92006

In Bouncy Castle for Java before 1.86, validation of an MLS RFC 9420 external commit's proposal list, org.bouncycastle.mls.protocol.Group.validateExternalCachedProposals, counted the proposals by type and bounded the removed leaf index but never established that the removed leaf had anything to d...