OpenSSL 3.5.9 is a security patch release. The most severe CVE fixed
in this release is High.

This release incorporates the following bug fixes and mitigations:

• Fixed DTLS retransmissions of handshake messages from a stale buffer offset.
  (CVE-2026-84782)

• Fixed excessive memory allocation in relative CRLDP processing.
  (CVE-2026-35189)

• Fixed QUIC unvalidated amplification credit may be over-accounted.
  (CVE-2026-35191)

• Fixed potential CPU DoS via O(n^2) fragment reassembly in QUIC.
  (CVE-2026-42772)

• Fixed a timing side-channel in scalar multiplication for mon-NIST EC curves.
  (CVE-2026-54872)

• Fixed QUIC STREAM fragment metadata DoS.
  (CVE-2026-54873)

• Fixed non-constant-time SM2 scalar multiplication on ARM64 and RISC-V.
  (CVE-2026-54875)

• Fixed out-of-bounds access after SSL_set_SSL_CTX() during a handshake.
  (CVE-2026-72897)

• Fixed QUIC connection-level flow control was not enforced for streams.
  (CVE-2026-75804)

• Fixed a NULL pointer dereference in CMP client revocation response handling.
  (CVE-2026-75805)

• Fixed an unauthenticated and undersized DTLS 1.2 AEAD record causing DoS.
  (CVE-2026-75806)

• Fixed a timing side-channel in SM2 signature generation.
  (CVE-2026-77696)

• Fixed an unbounded RETIRE_CONNECTION_ID backlog in QUIC stack
  implementation.
  (CVE-2026-84784)

• Fixed a bug where EVP_DecryptFinal() incorrectly reported a stale success
  on AES-SIV authentication failure.