CVE-2023-6237 | Excessive time spent checking invalid RSA public keys

Issue summary: Checking excessively long invalid RSA public keys may take a long time. Impact summary: Applications that use the function EVP_PKEY_public_check() to check RSA public keys may experience long delays. Where the key that is being checked has been obtained from an untrusted source this may lead to a Denial of Service. When function EVP_PKEY_public_check() is called on RSA public keys, a computation is done to confirm that the RSA modulus, n, is composite. For valid RSA keys, n is a product of two or more large primes and this computation completes quickly. However, if n is an overly large prime, then this computation would take a long time. An application that calls EVP_PKEY_public_check() and supplies an RSA key obtained from an untrusted source could be vulnerable to a Denial of Service attack. The function EVP_PKEY_public_check() is not called from other OpenSSL functions however it is called from the OpenSSL pkey command line application. For that reason that application is also vulnerable if used with the '-pubin' and '-check' options on untrusted data. The OpenSSL SSL/TLS implementation is not affected by this issue. The OpenSSL 3.0 and 3.1 FIPS providers are affected by this issue.

Published: 2024-04-25 Last update: 2026-05-12 Assigner: [email protected] Source: [email protected]
NVD Status：Deferred，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2023-6237 is rated Moderate Risk (50.4/100): CVSS Medium severity, with medium exploitation likelihood (EPSS 0.94%). Review affected assets and schedule 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-2023-6237

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 2026-06-02 0.97% 0.94% -0.03%
2 2026-05-22 0.94% 0.97% +0.03%
3 2026-05-14 — 0.94% —

Full EPSS history (22 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2023-6237

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:N/I:N/A:H 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:N)
Doesn’t really leak secrets in a meaningful way.
Integrity (I:N)
Data isn’t meaningfully altered or forged.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
 2.2 3.6 134c704f-9b21-4f2e-91b3-4a467353bcc0

Weakness enumeration for CVE-2023-6237

GitHub Security Advisory for CVE-2023-6237

GHSA-hvc4-mjv4-5mw6 · Severity: medium — Issue summary: Checking excessively long invalid RSA public keys may take a long time. Impact...

OS Trackers for CVE-2023-6237

vendor priority summary link
alpine — CVE-2023-6237: 1 source package rows (openssl); 7 state rows across 7 repos (3.17-main, 3.18-main, 3.19-main, 3.20-main, 3.21-main, 3.22-main, edge-main); fixed 7, open 0. https://security.alpinelinux.org/vuln/CVE-2023-6237
debian unimportant CVE-2023-6237 unimportant 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-2023-6237
redhat low — https://access.redhat.com/security/cve/CVE-2023-6237
suse medium CVE-2023-6237 severity moderate: SUSE including 81 source package names (compat-openssl098, edk2-ovmf-20240524-6.el9_5, …), 535 product×package rows across 62 product lines (SUSE CaaS Platform 4.0, SUSE Enterprise Storage 7.1, … (62 product lines)): Known Not Affected 455, Fixed 80. https://www.suse.com/security/cve/CVE-2023-6237/
ubuntu low CVE-2023-6237 low priority: Ubuntu including 4 source packages (edk2, nodejs, openssl, openssl1.0), 48 status rows across 12 suites (bionic, focal, jammy, lunar, mantic, noble, oracular, plucky, questing, trusty, upstream, xenial): not-affected 23, DNE 10, released 8, ignored 3, needs-triage 3, needed 1. https://ubuntu.com/security/CVE-2023-6237

Affected software / configurations for CVE-2023-6237

Vendor Product Version Raw CPE
No affected products in dataset.

References for CVE-2023-6237

cvelogic Threat Intelligence