CVE-2022-4304: 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...

Description

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.

Metrics

CVSS 3.1

5.9/10

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N

EPSS Probability

16.20%

96.5th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

Affected Software

Vendor	Product	Versions
Openssl	Openssl	>= 1.0.2, < 1.0.2zg
Openssl	Openssl	>= 1.1.1, < 1.1.1t
Openssl	Openssl	>= 3.0.0, < 3.0.8
Stormshield	Endpoint Security	< 7.2.40
Stormshield	Sslvpn	< 3.2.1
Stormshield	Stormshield Network Security	>= 2.7.0, < 2.7.11
Stormshield	Stormshield Network Security	>= 2.8.0, < 3.7.34
Stormshield	Stormshield Network Security	>= 3.8.0, < 3.11.22
Stormshield	Stormshield Network Security	>= 4.0.0, < 4.3.16
Stormshield	Stormshield Network Security	>= 4.4.0, < 4.6.3

References

Timeline

Published: Feb 8, 2023
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2022-4304?

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.

How severe is CVE-2022-4304?

CVE-2022-4304 has a CVSS score of 5.9/10 (MEDIUM severity). The EPSS model estimates a 16.20% probability of exploitation in the next 30 days.

How do I fix CVE-2022-4304?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.