CVE-2023-20031

A vulnerability in the SSL/TLS certificate handling of Snort 3 Detection Engine integration with Cisco Firepower Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to cause the Snort 3 detection engine to restart. This vulnerability is due to a logic error that occurs when an SSL/TLS certificate that is under load is accessed when it is initiating an SSL connection. Under specific, time-based constraints, an attacker could exploit this vulnerability by sending a high rate of SSL/TLS connection requests to be inspected by the Snort 3 detection engine on an affected device. A successful exploit could allow the attacker to cause the Snort 3 detection engine to reload, resulting in either a bypass or a denial of service (DoS) condition, depending on device configuration. The Snort detection engine will restart automatically. No manual intervention is required.

Published: 2023-11-01 Last update: 2026-06-17 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2023-20031 is rated Low Risk (23.2/100): CVSS Medium severity, with low exploitation likelihood (EPSS 0.28%). Monitor for updates and reassess as exploit intelligence or EPSS changes.

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-2023-20031

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 0.02% 0.28% +0.27%
2 2025-11-21 0.16% 0.02% -0.14%
3 2025-11-18 — 0.16% —

Full EPSS history (6 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2023-20031

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
4.0 3.1 MEDIUM
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:N/I:L/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:C)
Breaking this can reach past the original component and bite other resources—bigger blast radius.
Confidentiality (C:N)
Doesn’t really leak secrets in a meaningful way.
Integrity (I:L)
Attackers could change some data, but it’s limited—not everything goes.
Availability (A:N)
Service keeps running; no real outage angle.
 2.2 1.4 [email protected]
5.4 3.1 MEDIUM
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:N/I:L/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: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:C)
Breaking this can reach past the original component and bite other resources—bigger blast radius.
Confidentiality (C:N)
Doesn’t really leak secrets in a meaningful way.
Integrity (I:L)
Attackers could change some data, but it’s limited—not everything goes.
Availability (A:L)
Might cause slowdowns, glitches, or partial disruption—not a full brick.
 2.2 2.7 [email protected]

Weakness enumeration for CVE-2023-20031

OS Trackers for CVE-2023-20031

vendor priority summary link
ubuntu medium CVE-2023-20031 medium priority: Ubuntu including 1 source packages (snort), 9 status rows across 9 suites (bionic, focal, jammy, lunar, mantic, noble, trusty, upstream, xenial): not-affected 8, ignored 1. https://ubuntu.com/security/CVE-2023-20031

Affected software / configurations for CVE-2023-20031

Vendor Product Version Raw CPE
cisco firepower_threat_defense 6.7.0 cpe:2.3:a:cisco:firepower_threat_defense:6.7.0:*:*:*:*:*:*:*
cisco firepower_threat_defense 6.7.0.1 cpe:2.3:a:cisco:firepower_threat_defense:6.7.0.1:*:*:*:*:*:*:*
cisco firepower_threat_defense 6.7.0.2 cpe:2.3:a:cisco:firepower_threat_defense:6.7.0.2:*:*:*:*:*:*:*
cisco firepower_threat_defense 6.7.0.3 cpe:2.3:a:cisco:firepower_threat_defense:6.7.0.3:*:*:*:*:*:*:*
cisco firepower_threat_defense 7.0.0 cpe:2.3:a:cisco:firepower_threat_defense:7.0.0:*:*:*:*:*:*:*
cisco firepower_threat_defense 7.0.0.1 cpe:2.3:a:cisco:firepower_threat_defense:7.0.0.1:*:*:*:*:*:*:*
cisco firepower_threat_defense 7.0.1 cpe:2.3:a:cisco:firepower_threat_defense:7.0.1:*:*:*:*:*:*:*
cisco firepower_threat_defense 7.0.1.1 cpe:2.3:a:cisco:firepower_threat_defense:7.0.1.1:*:*:*:*:*:*:*
cisco firepower_threat_defense 7.0.2 cpe:2.3:a:cisco:firepower_threat_defense:7.0.2:*:*:*:*:*:*:*
cisco firepower_threat_defense 7.0.2.1 cpe:2.3:a:cisco:firepower_threat_defense:7.0.2.1:*:*:*:*:*:*:*
cisco firepower_threat_defense 7.0.3 cpe:2.3:a:cisco:firepower_threat_defense:7.0.3:*:*:*:*:*:*:*
cisco firepower_threat_defense 7.0.4 cpe:2.3:a:cisco:firepower_threat_defense:7.0.4:*:*:*:*:*:*:*
cisco firepower_threat_defense 7.0.5 cpe:2.3:a:cisco:firepower_threat_defense:7.0.5:*:*:*:*:*:*:*
cisco firepower_threat_defense 7.2.0 cpe:2.3:a:cisco:firepower_threat_defense:7.2.0:*:*:*:*:*:*:*
cisco firepower_threat_defense 7.2.0.1 cpe:2.3:a:cisco:firepower_threat_defense:7.2.0.1:*:*:*:*:*:*:*

References for CVE-2023-20031

cvelogic Threat Intelligence