Describe CVE-2019-13629.
What is CVE-2019-13629?
MatrixSSL 4.2.1 and earlier contains a timing side channel in ECDSA signature generation. This allows a local or a remote attacker, able to measure the duration of hundreds to thousands of signing operations, to compute the private key used. The issue occurs because crypto/pubkey/ecc_math.c scalar multiplication leaks the bit length of the scalar..