CVE-2022-4304 | Timing Oracle in RSA Decryption

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.

Published: 2023-02-08 Last update: 2025-11-04 Assigner: [email protected] Source: [email protected]

Conclusion & alert: CVE-2022-4304 is rated Moderate Risk (62.4/100): CVSS Medium severity, with high exploitation likelihood (EPSS 16.20%, 97th percentile). Core evidence: EPSS ranks this CVE among the most likely to be exploited in the near term. EPSS rose +15.98% over the last day, indicating growing attacker interest. Mandatory action: High exploitation likelihood—assess exposure and prioritize remediation.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Exploit prediction scoring system (EPSS) score for CVE-2022-4304

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-06-15 0.22% 16.20% +15.98%
2 2026-04-20 0.26% 0.22% -0.04%
3 2026-03-04 0.26%

Full EPSS history (32 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2022-4304

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
5.9 3.1 MEDIUM
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:H)
Even with access, the exploit needs extra luck, timing, or a fussy environment to actually work.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:H)
Serious risk that confidential data gets exposed in a big way.
Integrity (I:N)
Data isn’t meaningfully altered or forged.
Availability (A:N)
Service keeps running; no real outage angle.
2.2 3.6 [email protected]
5.9 3.1 MEDIUM
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:H)
Even with access, the exploit needs extra luck, timing, or a fussy environment to actually work.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:H)
Serious risk that confidential data gets exposed in a big way.
Integrity (I:N)
Data isn’t meaningfully altered or forged.
Availability (A:N)
Service keeps running; no real outage angle.
2.2 3.6 134c704f-9b21-4f2e-91b3-4a467353bcc0

Weakness enumeration for CVE-2022-4304

GitHub Security Advisory for CVE-2022-4304

GHSA-p52g-cm5j-mjv4 · Severity: medium · Ecosystem: rust — openssl-src subject to Timing Oracle in RSA Decryption

OS Trackers for CVE-2022-4304

vendor priority summary link
alpine CVE-2022-4304: 2 source package rows (openssl, openssl1.1-compat); 93 state rows across 10 repos (3.17-community, 3.17-main, 3.18-community, 3.18-main, 3.19-main, 3.20-main, 3.21-main, 3.22-main, edge-community, edge-main); fixed 10, open 83. https://security.alpinelinux.org/vuln/CVE-2022-4304
debian not yet assigned CVE-2022-4304 not yet assigned priority: Debian including 1 source packages (openssl), 5 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): resolved 5. https://security-tracker.debian.org/tracker/CVE-2022-4304
gentoo normal CVE-2022-4304: 1 GLSA(s) (202402-08), 1 atom(s) (dev-libs/openssl); latest impact normal. https://bugs.gentoo.org/buglist.cgi?quicksearch=CVE-2022-4304
redhat medium https://access.redhat.com/security/cve/CVE-2022-4304
suse medium CVE-2022-4304 severity moderate: SUSE including 667 source package names (0.23.0.3.2.527:libopenssl1_1-1.1.1d-150200.11.72.1, 0.23.0.3.2.527:libopenssl1_1-hmac-1.1.1d-150200.11.72.1, …), 1574 product×package rows across 343 product lines (Container bci/bci-base-fips, Container bci/bci-init, … (343 product lines)): Fixed 1356, Known Affected 129, Known Not Affected 59, Will Not Fix 30. https://www.suse.com/security/cve/CVE-2022-4304/
ubuntu medium CVE-2022-4304 medium priority: Ubuntu including 4 source packages (edk2, nodejs, openssl, openssl1.0), 46 status rows across 13 suites (bionic, focal, jammy, kinetic, lunar, mantic, noble, oracular, plucky, questing, trusty, upstream, xenial): not-affected 16, released 13, ignored 6, needs-triage 6, DNE 5. https://ubuntu.com/security/CVE-2022-4304

Affected software / configurations for CVE-2022-4304

Vendor Product Version Raw CPE
openssl openssl >= 1.0.2, < 1.0.2zg cpe:2.3:a:openssl:openssl:*:*:*:*:*:*:*:*
openssl openssl >= 1.1.1, < 1.1.1t cpe:2.3:a:openssl:openssl:*:*:*:*:*:*:*:*
openssl openssl >= 3.0.0, < 3.0.8 cpe:2.3:a:openssl:openssl:*:*:*:*:*:*:*:*
stormshield endpoint_security < 7.2.40 cpe:2.3:a:stormshield:endpoint_security:*:*:*:*:*:*:*:*
stormshield sslvpn < 3.2.1 cpe:2.3:a:stormshield:sslvpn:*:*:*:*:*:*:*:*
stormshield stormshield_network_security >= 2.7.0, < 2.7.11 cpe:2.3:a:stormshield:stormshield_network_security:*:*:*:*:*:*:*:*
stormshield stormshield_network_security >= 2.8.0, < 3.7.34 cpe:2.3:a:stormshield:stormshield_network_security:*:*:*:*:*:*:*:*
stormshield stormshield_network_security >= 3.8.0, < 3.11.22 cpe:2.3:a:stormshield:stormshield_network_security:*:*:*:*:*:*:*:*
stormshield stormshield_network_security >= 4.0.0, < 4.3.16 cpe:2.3:a:stormshield:stormshield_network_security:*:*:*:*:*:*:*:*
stormshield stormshield_network_security >= 4.4.0, < 4.6.3 cpe:2.3:a:stormshield:stormshield_network_security:*:*:*:*:*:*:*:*

References for CVE-2022-4304

cvelogic Threat Intelligence