OpenSSL 3.6.0 is a feature release adding significant new functionality to OpenSSL.

This release incorporates the following potentially significant or incompatible
changes:

• Added NIST security categories for PKEY objects.

• Added support for EVP_SKEY opaque symmetric key objects to the key
  derivation and key exchange provider methods. Added EVP_KDF_CTX_set_SKEY(),
  EVP_KDF_derive_SKEY(), and EVP_PKEY_derive_SKEY() functions.

• Added LMS signature verification support as per [SP 800-208]..
  This support is present in both the FIPS and default providers.

• An ANSI-C toolchain is no longer sufficient for building OpenSSL.
  The code should be built using compilers supporting C-99 features.

• Support for the VxWorks platforms has been removed.

• Added an openssl configutl utility for processing the OpenSSL
  configuration file and dumping the equal configuration file.

• Added support for FIPS 186-5 deterministic ECDSA signature
  generation to the FIPS provider.

• Deprecated EVP_PKEY_ASN1_METHOD-related functions.

OpenSSL 3.5.4 is a security patch release. The most severe CVE fixed in this
release is Moderate.

This release incorporates the following bug fixes and mitigations:

• Fix Out-of-bounds read & write in RFC 3211 KEK Unwrap.
  (CVE-2025-9230)

• Fix Timing side-channel in SM2 algorithm on 64 bit ARM.
  (CVE-2025-9231)

• Fix Out-of-bounds read in HTTP client no_proxy handling.
  (CVE-2025-9232)

• Reverted the synthesised OPENSSL_VERSION_NUMBER change for the release
  builds, as it broke some exiting applications that relied on the previous
  3.x semantics, as documented in OpenSSL_version(3).

OpenSSL 3.4.3 is a security patch release. The most severe CVE fixed in this
release is Moderate.

This release incorporates the following bug fixes and mitigations:

• Fix Out-of-bounds read & write in RFC 3211 KEK Unwrap.
  (CVE-2025-9230)

• Fix Timing side-channel in SM2 algorithm on 64 bit ARM.
  (CVE-2025-9231)

• Fix Out-of-bounds read in HTTP client no_proxy handling.
  (CVE-2025-9232)

OpenSSL 3.3.5 is a security patch release. The most severe CVE fixed in this
release is Moderate.

This release incorporates the following bug fixes and mitigations:

• Fix Out-of-bounds read & write in RFC 3211 KEK Unwrap.
  (CVE-2025-9230)

• Fix Timing side-channel in SM2 algorithm on 64 bit ARM.
  (CVE-2025-9231)

• Fix Out-of-bounds read in HTTP client no_proxy handling.
  (CVE-2025-9232)

OpenSSL 3.2.6 is a security patch release. The most severe CVE fixed in this
release is Moderate.

This release incorporates the following bug fixes and mitigations:

• Fix Out-of-bounds read & write in RFC 3211 KEK Unwrap.
  (CVE-2025-9230)

• Fix Timing side-channel in SM2 algorithm on 64 bit ARM.
  (CVE-2025-9231)

• Fix Out-of-bounds read in HTTP client no_proxy handling.
  (CVE-2025-9232)

OpenSSL 3.0.18 is a security patch release. The most severe CVE fixed in this
release is Moderate.

This release incorporates the following bug fixes and mitigations:

• Fix Out-of-bounds read & write in RFC 3211 KEK Unwrap.
  (CVE-2025-9230)

• Fix Out-of-bounds read in HTTP client no_proxy handling.
  (CVE-2025-9232)

OpenSSL 3.5.3 is a bug fix release.

This release incorporates the following bug fixes and mitigations:

• Added FIPS 140-3 PCT on DH key generation.
• Fixed the synthesised OPENSSL_VERSION_NUMBER.

OpenSSL 3.6.0-beta1 is a feature pre-release adding significant new functionality to OpenSSL.

This release incorporates the following features, bug fixes and mitigations:

• Added FIPS 140-3 PCT on DH key generation.

• Added NIST security categories for PKEY objects.

• Added support for EVP_SKEY opaque symmetric key objects to the key
  derivation and key exchange provider methods. Added EVP_KDF_CTX_set_SKEY(),
  EVP_KDF_derive_SKEY(), and EVP_PKEY_derive_SKEY() functions.

• Added LMS signature verification support as per [SP 800-208]. This
  support is present in both the FIPS and default providers.

• An ANSI-C toolchain is no longer sufficient for building OpenSSL. The code
  should build on compilers supporting C-99 features.

• The VxWorks platforms have been removed.

• Added an openssl configutl utility for processing the OpenSSL
  configuration file and dumping the equal configuration file.

• Added support for FIPS 186-5 deterministic ECDSA signature
  generation to the FIPS provider.

• Deprecated EVP_PKEY_ASN1_METHOD related functions.

OpenSSL 3.6.0 is a feature pre-release adding significant new functionality to openssl

This release incorporates the following features, bug fixes and mitigations:

• Added PCT for key import for SLH-DSA when in FIPS mode.

• Added FIPS 140-3 PCT on DH key generation.

• Added NIST security categories for PKEY objects.

• Added support for EVP_SKEY opaque symmetric key objects to the key
  derivation and key exchange provider methods. Added EVP_KDF_CTX_set_SKEY(),
  EVP_KDF_derive_SKEY(), and EVP_PKEY_derive_SKEY() functions.

• The FIPS provider now performs a PCT on key import for RSA, EC and ECX.
  This is mandated by FIPS 140-3 IG 10.3.A additional comment 1.

• Added LMS signature verification support as per [SP 800-208]. This
  support is present in both the FIPS and default providers.

• An ANSI-C toolchain is no longer sufficient for building OpenSSL. The code
  should build on compilers supporting C-99 features.

• The VxWorks platforms have been removed.

• Added an openssl configutl utility for processing the openssl
  configuration file and dumping the equal configuration file.

• Added support for FIPS 186-5 deterministic ECDSA signature
  generation to the FIPS provider.

• Deprecated EVP_PKEY_ASN1_METHOD related functions.

OpenSSL 3.5.2 is a bug fix release.

This release incorporates the following bug fixes and mitigations:

• Miscellaneous minor bug fixes.
• The FIPS provider now performs a PCT on key import for RSA, EC and ECX.
  This is mandated by FIPS 140-3 IG 10.3.A additional comment 1.