A security vulnerability has been identified in all supported versions of OpenSSL related to the verification of X.509 certificate chains that include policy constraints. Attackers may be able to exploit this vulnerability by creating a malicious certificate chain that triggers exponential use of computational resources, leading to a denial-of-service attack on affected systems. Policy processing is disabled by default but can be enabled by passing the `-policy' argument to the command line utilities or by calling the `X509_VERIFY_PARAM_set1_policies' function. Applications that use a non-default option when verifying certificates may be vulnerable to an attack from a malicious CA to circumvent certain checks. Invalid certificate policies in leaf certificates are silently ignored by OpenSSL and other certificate policy checks are skipped for that certificate. A malicious CA could use this to deliberately assert invalid certificate policies in order to circumvent policy checking on the certificate altogether. Policy processing is disabled by default but can be enabled by passing the `-policy' argument to the command line utilities or by calling the `X509_VERIFY_PARAM_set1_policies' function. The function X509_VERIFY_PARAM_add0_policy is documented to implicitly enable the certificate policy check when doing certificate verification. However the implementation of the function does not enable the check which allows certificates with invalid or incorrect policies to pass the certificate verification. As suddenly enabling the policy check could break existing deployments it was decided to keep the existing behavior of the X509_VERIFY_PARAM_add0_policy function. Instead the applications that require OpenSSL to perform certificate policy check need to use X509_VERIFY_PARAM_set1_policies or explicitly enable the policy check by calling X509_VERIFY_PARAM_set_flags with the X509_V_FLAG_POLICY_CHECK flag argument. Certificate policy checks are disabled by default in OpenSSL and are not commonly used by applications. Issue summary: The AES-XTS cipher decryption implementation for 64 bit ARMplatform contains a bug that could cause it to read past the input buffer,leading to a crash.Impact summary: Applications that use the AES-XTS algorithm on the 64 bit ARMplatform can crash in rare circumstances. The AES-XTS algorithm is usuallyused for disk encryption.The AES-XTS cipher decryption implementation for 64 bit ARM platform will readpast the end of the ciphertext buffer if the ciphertext size is 4 mod 5 in 16byte blocks, e.g. 144 bytes or 1024 bytes. If the memory after the ciphertextbuffer is unmapped, this will trigger a crash which results in a denial ofservice.If an attacker can control the size and location of the ciphertext bufferbeing decrypted by an application using AES-XTS on 64 bit ARM, theapplication is affected. This is fairly unlikely making this issuea Low severity one