Updated: 2023-11-07 19:11:03.344865


A timing based side channel exists in the OpenSSL RSA Decryption implementation which could be sufficient to recover a plaintext across a network in a Bleichenbacher style attack. To achieve a successful decryption an attacker would have to be able to send a very large number of trial messages for decryption. The vulnerability affects all RSA padding modes: PKCS#1 v1.5, RSA-OEAP and RSASVE. For example, in a TLS connection, RSA is commonly used by a client to send an encrypted pre-master secret to the server. An attacker that had observed a genuine connection between a client and a server could use this flaw to send trial messages to the server and record the time taken to process them. After a sufficiently large number of messages the attacker could recover the pre-master secret used for the original connection and thus be able to decrypt the application data sent over that connection.



Severity Score
CVSS Version 2.x 0
CVSS Version 3.x MEDIUM 5.9


OS name Project name Version Score Severity Status Errata Last updated
AlmaLinux 9.2 ESU openssl 3.0.7 5.9 MEDIUM Ignored 2023-11-08 04:07:54
AlmaLinux 9.2 FIPS openssl 3.0.7 5.9 MEDIUM Ignored 2023-11-21 04:12:28
CentOS 7 ELS openssl 1.0.2k 5.9 MEDIUM Ignored 2023-10-26 11:09:36
CentOS 8.4 ELS openssl 1.1.1g 5.9 MEDIUM Released CLSA-2023:1680206329 2023-03-30 17:04:32
CentOS 8.5 ELS openssl 1.1.1k 5.9 MEDIUM Released CLSA-2023:1680210075 2023-03-30 17:04:31
Ubuntu 16.04 ELS openssl 1.0.2g-1 5.9 MEDIUM Ignored 2023-10-26 11:09:36
Ubuntu 18.04 ELS openssl 1.1.1-1 5.9 MEDIUM Already Fixed 2023-11-06 08:36:22