Skip to content
Sign in
8.7 High

CVE-2026-63566 Memory allocation with excessive size value in the DTLS handshake reassembly (DtlsReliableHandshake, DtlsReassembler) in…

Description

Memory allocation with excessive size value in the DTLS handshake reassembly (DtlsReliableHandshake, DtlsReassembler) in Legion of the Bouncy Castle Inc. bc-csharp before 2.7.0 allows a remote unauthenticated DTLS peer to cause a denial of service through memory exhaustion via crafted handshake message fragments, because the reassembly buffer for each incoming handshake message was allocated at the 24-bit length declared in the fragment header, without the check against the peer's maximum handshake message size that TLS already applied. A fragment carrying no payload can force an allocation of almost 16 MB, for each of up to 16 pending messages per handshake, before the handshake is authenticated. DTLS servers and DTLS clients are both affected; TLS is not.

Affected products and versions

Product Affected versions Fixed in
bc-csharp 2.7 earliest → < 2.7.0 2.7.0

Other CVEs of bc-csharp

The 21 CVEs of bc-csharp →
CVE-2026-103604 Inefficient algorithmic complexity in X.509 distinguished name string conversion (X509Name.ToString and… 8.7 High CVE-2026-103603 Memory allocation with excessive size value in the HSS/LMS signature code (HssPublicKeyParameters, HssSignature) in… 8.7 High CVE-2026-103602 Improper certificate validation in PkixNameConstraintValidator in Legion of the Bouncy Castle Inc 8.2 High CVE-2026-103601 Release of unverified plaintext in the CCM (CcmBlockCipher) and DSTU 7624 CCM (KCcmBlockCipher) AEAD modes in Legion… 8.2 High
Track this CVE