--- title: "CVE-2022-4304\n | Ubuntu" description: Ubuntu is an open source software operating system that runs from the desktop, to the cloud, to all your internet connected things. url: https://ubuntu.com/security/CVE-2022-4304?format=md keywords: index, follow --- # CVE-2022-4304 Publication date 7 February 2023 Last updated 26 November 2025 --- Ubuntu priority **Medium** [Why this priority?](https://ubuntu.com/security/cves/about#priority ) ## Cvss 3 Severity Score **5.9 · Medium** [Score breakdown](https://ubuntu.com/security/CVE-2022-4304?format=md#impact-score) Toggle side navigation ## 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. [Read the notes from the security team](https://ubuntu.com/security/CVE-2022-4304?format=md#notes) ## Status Show unmaintained releases | Package | Ubuntu Release | Status | | --- | --- | --- | | edk2 | 26.04 LTS resolute | Not affected | | 25.10 questing | Not affected | | 25.04 plucky | Not affected | | 24.10 oracular | Not affected | | 24.04 LTS noble | Not affected | | 23.10 mantic | Not affected | | 23.04 lunar | Ignored end of life, was needs-triage | | 22.10 kinetic | Ignored end of life, was needs-triage | | 22.04 LTS jammy | Fixed 2022.02-3ubuntu0.22.04.4 | | 20.04 LTS focal | Needs evaluation | | 18.04 LTS bionic | Needs evaluation | | 16.04 LTS xenial | Needs evaluation | | 14.04 LTS trusty | Ignored end of standard support | | nodejs | 26.04 LTS resolute | Not affected | | 25.10 questing | Not affected | | 25.04 plucky | Not affected | | 24.10 oracular | Not affected | | 24.04 LTS noble | Not affected | | 23.10 mantic | Not affected | | 23.04 lunar | Not affected | | 22.10 kinetic | Not affected | | 22.04 LTS jammy | Fixed 12.22.9~dfsg-1ubuntu3.3 | | 20.04 LTS focal | Not affected | | 18.04 LTS bionic | Not affected | | 16.04 LTS xenial | Not affected | | 14.04 LTS trusty | Not affected | | openssl | 26.04 LTS resolute | Fixed 3.0.8-1ubuntu1 | | 25.10 questing | Fixed 3.0.8-1ubuntu1 | | 25.04 plucky | Fixed 3.0.8-1ubuntu1 | | 24.10 oracular | Fixed 3.0.8-1ubuntu1 | | 24.04 LTS noble | Fixed 3.0.8-1ubuntu1 | | 23.10 mantic | Fixed 3.0.8-1ubuntu1 | | 23.04 lunar | Fixed 3.0.8-1ubuntu1 | | 22.10 kinetic | Fixed 3.0.5-2ubuntu2.1 | | 22.04 LTS jammy | Fixed 3.0.2-0ubuntu1.8 | | 20.04 LTS focal | Fixed 1.1.1f-1ubuntu2.17 | | 18.04 LTS bionic | Fixed 1.1.1-1ubuntu2.1~18.04.21 | | 16.04 LTS xenial | Ignored end of standard support | | 14.04 LTS trusty | Ignored end of standard support | | openssl1.0 | 22.10 kinetic | Not in release | | 22.04 LTS jammy | Not in release | | 20.04 LTS focal | Not in release | | 18.04 LTS bionic | Ignored | | 16.04 LTS xenial | Not in release | | 14.04 LTS trusty | Not in release | --- * [How can I get the fixes?](https://ubuntu.com/security/cves/about#security) * [What do statuses mean?](https://ubuntu.com/security/cves/about#statuses) ## Notes --- ### [mdeslaur](https://launchpad.net/~mdeslaur) Due to the substantial code changes required to fix this side channel issue and others like it in the 1.0.2 and earlier codebases, we will not be fixing this issue in bionic and earlier to not introduce possible regressions. The commit was later reverted, and a more simplified fix was used, see: https://git.openssl.org/gitweb/?p=openssl.git;a=commit;h=0372649a943fb23f7f08c7acdbc01464b9df03f0 https://git.openssl.org/gitweb/?p=openssl.git;a=commit;h=3f499b24f3bcd66db022074f7e8b4f6ee266a3ae ## Severity score breakdown CVSS version: CVSS v3.0 **Base score** 5.9 · Medium * Base metrics | Parameter | Value | | --- | --- | | Attack vector | Network | | Attack complexity | High | | Privileges required | None | | User interaction | None | | Scope | Unchanged | | Confidentiality impact | High | | Integrity impact | None | | Availability impact | None | * Scores | Parameter | Value | | --- | --- | | Base score | 5.9 · Medium | | Exploitability score | - | | Impact score | - | **Vector:** CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N ## References * [MITRE](https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2022-4304) * [NVD](https://nvd.nist.gov/vuln/detail/CVE-2022-4304) * [Launchpad](https://launchpad.net/bugs/cve/CVE-2022-4304) * [Debian](https://security-tracker.debian.org/tracker/CVE-2022-4304) ### Related Ubuntu Security Notices (USN) + [USN-5844-1](https://usn.ubuntu.com/USN-5844-1) + OpenSSL vulnerabilities + 7 February 2023 + [USN-6564-1](https://usn.ubuntu.com/USN-6564-1) + Node.js vulnerabilities + 3 January 2024 + [USN-7894-1](https://usn.ubuntu.com/USN-7894-1) + EDK II vulnerabilities + 26 November 2025 ### Other references * *