Cyber Resilience

CVE-2023-20083

DoS in Cisco Secure Firewall Threat Defense 6.2.3 – 6.2.3.18

DoS
Published
01 November 2023
Modified
11 August 2026
Patch / advisory
View advisory
CVSS Score v3.1 8.6
Click a component to see what it means
Raw vectorCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H
EPSS Score 0.0069 50th percentile
Risk Priority 63 floored blend · peak EPSS

Summary

CVE-2023-20083 is a high-severity Infinite Loop (CWE-835) vulnerability in Cisco Secure Firewall Threat Defense. Its CVSS base score is 8.6 (High).

Operationally, exploitation aligns with the MITRE ATT&CK technique Application or System Exploitation (T1499.004); ranked at the 50th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.

EU & UK References

Vulnerability Data

A vulnerability in ICMPv6 inspection when configured with the Snort 2 detection engine for Cisco Firepower Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to cause the CPU of an affected device to spike to 100 percent, which…

more

could stop all traffic processing and result in a denial of service (DoS) condition. FTD management traffic is not affected by this vulnerability. This vulnerability is due to improper error checking when parsing fields within the ICMPv6 header. An attacker could exploit this vulnerability by sending a crafted ICMPv6 packet through an affected device. A successful exploit could allow the attacker to cause the device to exhaust CPU resources and stop processing traffic, resulting in a DoS condition. Note: To recover from the DoS condition, the Snort 2 Detection Engine or the Cisco FTD device may need to be restarted.

CWE(s)
CWE-835NVD-CWE-noinfo

Related Threats

MITRE ATT&CK Enterprise Techniques

T1499.004 Application or System Exploitation Impact
Adversaries may exploit software vulnerabilities that can cause an application or system to crash and deny availability to users.
attack.mitre.org →
T1499 Endpoint Denial of Service Impact
Adversaries may perform Endpoint Denial of Service (DoS) attacks to degrade or block the availability of services to users.
attack.mitre.org →
T1499.003 Application Exhaustion Flood Impact
Adversaries may target resource intensive features of applications to cause a denial of service (DoS), denying availability to those applications.
attack.mitre.org →
Derived from this CVE’s CWE(s) via the direct CWE→ATT&CK cross-walk.

CVEs Like This One

CVE-2024-20353Same product: Cisco Secure Firewall Threat Defense
CVE-2024-20339Same product: Cisco Secure Firewall Threat Defense
CVE-2026-20050Same product: Cisco Secure Firewall Threat Defense
CVE-2024-20351Same product: Cisco Secure Firewall Threat Defense
CVE-2023-20031Same product: Cisco Secure Firewall Threat Defense
CVE-2023-20177Same product: Cisco Secure Firewall Threat Defense
CVE-2023-20267Same product: Cisco Secure Firewall Threat Defense
CVE-2026-20017Same product: Cisco Secure Firewall Threat Defense
CVE-2024-20407Same product: Cisco Secure Firewall Threat Defense
CVE-2023-25653Same vendor: Cisco

Affected Assets

cisco
secure firewall threat defense
6.2.3 — 6.2.3.18 · 6.4.0 — 6.4.0.17 · 6.6.0 — 6.6.7.1

Mitigating Controls

Likely Mitigating Controls AI

Per-CVE control mapping for this CVE has not run yet; the list below is derived from the weakness types (CWEs) cited in the NVD entry.

CP-7 Alternate Processing Site
addresses: CWE-835

Enables transfer to alternate site if an infinite loop at the primary renders processing unavailable.

SC-5 Denial-of-service Protection
addresses: CWE-835

Detects and mitigates infinite loops that produce sustained resource consumption.

Mitigating Controls (NIST CSF 2.0) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.

PR.PS-06 mostly match
prevents

Secure SDLC practices (reviews, testing, static analysis) directly prevent introduction of infinite-loop defects.

ID.RA-01 partial match
prevents

Static analysis and vuln scanning during asset assessment can detect unreachable loop exits.

Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.

A.8.29 Security testing in development and acceptance mostly match
finds

Security testing can uncover infinite-loop conditions before release.

A.8.25 Secure development life cycle partial match
prevents

Secure development life cycle mandates practices that can detect and prevent infinite-loop defects.

A.8.26 Application security requirements partial match
prevents

Application security requirements can specify loop-termination rules, indirectly reducing the weakness.

A.8.28 Secure coding partial match
prevents

Secure coding standards directly address loop termination and prevent infinite loops.

A.8.27 Secure system architecture and engineering principles none match
none

Secure architecture principles encourage designs that avoid unreachable exit conditions.

A.8.32 Change management none match
none

Change management can require review of loop logic when code is modified.

References