CVE-2026-18036 NTRU leaks private key information by reducing secret values with a non-constant-time integer division

In Bouncy Castle for Java before 1.86, NTRU reduced secret values with the % operator in three helpers whose reference implementations are deliberately division-free, so each reduction was carried out by an integer division whose latency depends on the secret operand. Polynomial.modQ divided by a...

CVE-2026-18036 NTRU leaks private key information by reducing secret values with a non-constant-time integer division

In Bouncy Castle for Java before 1.86, NTRU reduced secret values with the % operator in three helpers whose reference implementations are deliberately division-free, so each reduction was carried out by an integer division whose latency depends on the secret operand. Polynomial.modQ divided by a...

CVE-2026-18036 NTRU leaks private key information by reducing secret values with a non-constant-time integer division

In Bouncy Castle for Java before 1.86, NTRU reduced secret values with the % operator in three helpers whose reference implementations are deliberately division-free, so each reduction was carried out by an integer division whose latency depends on the secret operand. Polynomial.modQ divided by a...

CVE-2026-17508

In Bouncy Castle for Java before 1.86, several password-based key derivation entry points ran the KDF with cost parameters taken from the untrusted input being processed, without bounding them, so a small input could dictate an arbitrary amount of work before any password or integrity check could...

CVE-2026-63569

Improper input validation in DHAgreement.CalculateAgreement MTI/A0 two-pass Diffie-Hellman in Legion of the Bouncy Castle Inc. bc-csharp before 2.7.0 allows an on-path attacker to make the local party compute an agreed value the attacker already knows, defeating the key authentication MTI/A0 is...

CVE-2026-16001

Exposure of the message authentication key through the encryption keystream in the stream mode of IesEngine an IesEngine constructed without a block cipher in Legion of the Bouncy Castle Inc. bc-csharp before 2.7.0 allows a remote attacker who has observed one encrypted message with known plainte...

CVE-2026-103603 Unbounded HSS public key level count allows huge array allocation during signature verification

Memory allocation with excessive size value in the HSS/LMS signature code HssPublicKeyParameters, HssSignature in Legion of the Bouncy Castle Inc. bc-csharp before 2.7.0 allows a remote unauthenticated attacker who can supply both an HSS public key and a signature to cause a denial of service...

EUVD-2026-91233

Memory allocation with excessive size value in the HSS/LMS signature code HssPublicKeyParameters, HssSignature in Legion of the Bouncy Castle Inc. bc-csharp before 2.7.0 allows a remote unauthenticated attacker who can supply both an HSS public key and a signature to cause a denial of service...

CVE-2026-63578

The bc-csharp library (versions before 2.7.0 ) by Legion of the Bouncy Castle Inc. is vulnerable to a denial of service via CPU exhaustion in the PbeUtilities.GenerateCipherParameters function. This is caused by the allocation of resources without limits during password-based private-key decrypti...

EUVD-2026-91229

Allocation of resources without limits in password-based private-key decryption PbeUtilities.GenerateCipherParameters in Legion of the Bouncy Castle Inc. bc-csharp before 2.7.0 allows an attacker who can supply an encrypted private key, such as a PKCS8 EncryptedPrivateKeyInfo or "ENCRYPTED PRIVAT...

EUVD-2026-91224

Observable discrepancy in the CMS RSA PKCS1 v1.5 key-transport unwrap KeyTransRecipientInformation.UnwrapKey in Legion of the Bouncy Castle Inc. bc-csharp before 2.7.0 allows a remote attacker who holds a captured CMS EnvelopedData message, and who can submit many modified messages to an...

CVE-2026-63573 Bleichenbacher padding oracle in CMS RSA PKCS#1 v1.5 key-transport unwrap

Observable discrepancy in the CMS RSA PKCS1 v1.5 key-transport unwrap KeyTransRecipientInformation.UnwrapKey in Legion of the Bouncy Castle Inc. bc-csharp before 2.7.0 allows a remote attacker who holds a captured CMS EnvelopedData message, and who can submit many modified messages to an...

CVE-2026-63573 Bleichenbacher padding oracle in CMS RSA PKCS#1 v1.5 key-transport unwrap

Observable discrepancy in the CMS RSA PKCS1 v1.5 key-transport unwrap KeyTransRecipientInformation.UnwrapKey in Legion of the Bouncy Castle Inc. bc-csharp before 2.7.0 allows a remote attacker who holds a captured CMS EnvelopedData message, and who can submit many modified messages to an...

CVE-2026-63573 Bleichenbacher padding oracle in CMS RSA PKCS#1 v1.5 key-transport unwrap

Observable discrepancy in the CMS RSA PKCS1 v1.5 key-transport unwrap KeyTransRecipientInformation.UnwrapKey in Legion of the Bouncy Castle Inc. bc-csharp before 2.7.0 allows a remote attacker who holds a captured CMS EnvelopedData message, and who can submit many modified messages to an...

CVE-2026-63569 MTI/A0 DHAgreement does not validate the peer's ephemeral value

Improper input validation in DHAgreement.CalculateAgreement MTI/A0 two-pass Diffie-Hellman in Legion of the Bouncy Castle Inc. bc-csharp before 2.7.0 allows an on-path attacker to make the local party compute an agreed value the attacker already knows, defeating the key authentication MTI/A0 is...

CVE-2026-63569

The bc-csharp library by Legion of the Bouncy Castle Inc. (versions before 2.7.0 ) is vulnerable to improper input validation in the DHAgreement.CalculateAgreement function during MTI/A0 two-pass Diffie-Hellman key exchanges. An on-path attacker can provide a crafted out-of-range or small-order e...

CVE-2026-63569 MTI/A0 DHAgreement does not validate the peer's ephemeral value

Improper input validation in DHAgreement.CalculateAgreement MTI/A0 two-pass Diffie-Hellman in Legion of the Bouncy Castle Inc. bc-csharp before 2.7.0 allows an on-path attacker to make the local party compute an agreed value the attacker already knows, defeating the key authentication MTI/A0 is...

EUVD-2026-91220

Improper input validation in DHAgreement.CalculateAgreement MTI/A0 two-pass Diffie-Hellman in Legion of the Bouncy Castle Inc. bc-csharp before 2.7.0 allows an on-path attacker to make the local party compute an agreed value the attacker already knows, defeating the key authentication MTI/A0 is...

CVE-2026-63569 MTI/A0 DHAgreement does not validate the peer's ephemeral value

Improper input validation in DHAgreement.CalculateAgreement MTI/A0 two-pass Diffie-Hellman in Legion of the Bouncy Castle Inc. bc-csharp before 2.7.0 allows an on-path attacker to make the local party compute an agreed value the attacker already knows, defeating the key authentication MTI/A0 is...

CVE-2026-16001

The Bouncy Castle Inc. bc-csharp library (versions before 2.7.0 ) is vulnerable to a message authentication key exposure in the IesEngine stream mode. Specifically, when an IesEngine is constructed without a block cipher, the MAC key is taken from the key derivation output immediately following a...