CVE-2023-5678 | Excessive time spent in DH check / generation with large Q parameter value

Issue summary: Generating excessively long X9.42 DH keys or checking excessively long X9.42 DH keys or parameters may be very slow. Impact summary: Applications that use the functions DH_generate_key() to generate an X9.42 DH key may experience long delays. Likewise, applications that use DH_check_pub_key(), DH_check_pub_key_ex() or EVP_PKEY_public_check() to check an X9.42 DH key or X9.42 DH parameters may experience long delays. Where the key or parameters that are being checked have been obtained from an untrusted source this may lead to a Denial of Service. While DH_check() performs all the necessary checks (as of CVE-2023-3817), DH_check_pub_key() doesn't make any of these checks, and is therefore vulnerable for excessively large P and Q parameters. Likewise, while DH_generate_key() performs a check for an excessively large P, it doesn't check for an excessively large Q. An application that calls DH_generate_key() or DH_check_pub_key() and supplies a key or parameters obtained from an untrusted source could be vulnerable to a Denial of Service attack. DH_generate_key() and DH_check_pub_key() are also called by a number of other OpenSSL functions. An application calling any of those other functions may similarly be affected. The other functions affected by this are DH_check_pub_key_ex(), EVP_PKEY_public_check(), and EVP_PKEY_generate(). Also vulnerable are the OpenSSL pkey command line application when using the "-pubcheck" option, as well as the OpenSSL genpkey command line application. The OpenSSL SSL/TLS implementation is not affected by this issue. The OpenSSL 3.0 and 3.1 FIPS providers are not affected by this issue.

Published: 2023-11-06 Last update: 2026-05-12 Assigner: [email protected] Source: [email protected]

Conclusion & alert: CVE-2023-5678 is rated Moderate Risk (44.8/100): CVSS Medium severity, with medium exploitation likelihood (EPSS 0.54%). Mandatory action: 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-2023-5678

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 2026-05-12 0.64% 0.54% -0.10%
2 2026-05-10 0.66% 0.64% -0.02%
3 2026-04-27 0.66%

Full EPSS history (24 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2023-5678

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
5.3 3.1 MEDIUM
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L 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:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
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:L)
Might cause slowdowns, glitches, or partial disruption—not a full brick.
3.9 1.4 [email protected]
5.3 3.1 MEDIUM
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L 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:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
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:L)
Might cause slowdowns, glitches, or partial disruption—not a full brick.
3.9 1.4 134c704f-9b21-4f2e-91b3-4a467353bcc0

Weakness enumeration for CVE-2023-5678

GitHub Security Advisory for CVE-2023-5678

GHSA-2cj7-mg3x-9mhq · Severity: high — Issue summary: Generating excessively long X9.42 DH keys or checking excessively long X9.42 DH...

OS Trackers for CVE-2023-5678

vendor priority summary link
alpine CVE-2023-5678: 1 source package rows (openssl); 164 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 33, open 131. https://security.alpinelinux.org/vuln/CVE-2023-5678
debian not yet assigned CVE-2023-5678 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-2023-5678
redhat low https://access.redhat.com/security/cve/CVE-2023-5678
suse medium CVE-2023-5678 severity moderate: SUSE including 532 source package names (1.2.3-2.2.63:libopenssl1_1-1.1.1l-150400.7.60.2, 1.2.3-3.2.78:libopenssl1_1-1.1.1l-150400.7.60.2, …), 1303 product×package rows across 300 product lines (Container bci/bci-base-fips, Container bci/bci-init, … (300 product lines)): Fixed 1030, Known Affected 185, Known Not Affected 88. https://www.suse.com/security/cve/CVE-2023-5678/
ubuntu low CVE-2023-5678 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 13, released 13, DNE 10, ignored 5, needs-triage 4, needed 3. https://ubuntu.com/security/CVE-2023-5678

Affected software / configurations for CVE-2023-5678

Vendor Product Version Raw CPE
openssl openssl >= 1.0.2, < 1.0.2zj cpe:2.3:a:openssl:openssl:*:*:*:*:*:*:*:*
openssl openssl >= 1.1.1, < 1.1.1x cpe:2.3:a:openssl:openssl:*:*:*:*:*:*:*:*
openssl openssl >= 3.0.0, < 3.0.13 cpe:2.3:a:openssl:openssl:*:*:*:*:*:*:*:*
openssl openssl >= 3.1.0, < 3.1.5 cpe:2.3:a:openssl:openssl:*:*:*:*:*:*:*:*

References for CVE-2023-5678

URL Tags
https://git.openssl.org/gitweb/?p=openssl.git;a=commitdiff;h=34efaef6c103d636ab507a0cc34dca4d3aecc055 Broken Link
https://git.openssl.org/gitweb/?p=openssl.git;a=commitdiff;h=710fee740904b6290fef0dd5536fbcedbc38ff0c Broken Link
https://git.openssl.org/gitweb/?p=openssl.git;a=commitdiff;h=db925ae2e65d0d925adef429afc37f75bd1c2017 Mailing List Patch
https://git.openssl.org/gitweb/?p=openssl.git;a=commitdiff;h=ddeb4b6c6d527e54ce9a99cba785c0f7776e54b6 Mailing List Patch
https://www.openssl.org/news/secadv/20231106.txt Vendor Advisory
http://www.openwall.com/lists/oss-security/2024/03/11/1
https://lists.debian.org/debian-lts-announce/2024/10/msg00033.html
https://lists.debian.org/debian-lts-announce/2024/11/msg00000.html
https://security.netapp.com/advisory/ntap-20231130-0010/
https://cert-portal.siemens.com/productcert/html/ssa-093430.html
https://cert-portal.siemens.com/productcert/html/ssa-128433.html
https://cert-portal.siemens.com/productcert/html/ssa-265688.html
https://cert-portal.siemens.com/productcert/html/ssa-277137.html
https://cert-portal.siemens.com/productcert/html/ssa-331112.html
https://cert-portal.siemens.com/productcert/html/ssa-341067.html
https://cert-portal.siemens.com/productcert/html/ssa-398330.html
https://cert-portal.siemens.com/productcert/html/ssa-556635.html
https://cert-portal.siemens.com/productcert/html/ssa-613116.html
https://cert-portal.siemens.com/productcert/html/ssa-769027.html
https://cert-portal.siemens.com/productcert/html/ssa-794697.html
https://cert-portal.siemens.com/productcert/html/ssa-915275.html
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