Cyber Resilience

CVE-2023-44203

Juniper Junos ≤ 20.4

Published
13 October 2023
Modified
21 November 2024
Patch / advisory
CVSS Score v3.1 6.5
Click a component to see what it means
Raw vectorCVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
EPSS Score 0.0027 19th percentile
Risk Priority 49 floored blend · peak EPSS

Summary

CVE-2023-44203 is a medium-severity Improper Check or Handling of Exceptional Conditions (CWE-703) vulnerability in Juniper Junos. Its CVSS base score is 6.5 (Medium).

Operationally, exploitation aligns with the MITRE ATT&CK technique Endpoint Denial of Service (T1499); ranked at the 19th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.

OWASP Top 10 for Web (2025)

EU & UK References

Vulnerability Data

An Improper Check or Handling of Exceptional Conditions vulnerability in the Packet Forwarding Engine (pfe) of Juniper Networks Junos OS on QFX5000 Series, EX2300, EX3400, EX4100, EX4400 and EX4600 allows a adjacent attacker to send specific traffic, which leads to…

more

packet flooding, resulting in a Denial of Service (DoS). When a specific IGMP packet is received in an isolated VLAN, it is duplicated to all other ports under the primary VLAN, which causes a flood. This issue affects QFX5000 series, EX2300, EX3400, EX4100, EX4400 and EX4600 platforms only. This issue affects Juniper Junos OS on on QFX5000 Series, EX2300, EX3400, EX4100, EX4400 and EX4600: * All versions prior to 20.4R3-S5; * 21.1 versions prior to 21.1R3-S4; * 21.2 versions prior to 21.2R3-S3; * 21.3 versions prior to 21.3R3-S5; * 21.4 versions prior to 21.4R3-S2; * 22.1 versions prior to 22.1R3; * 22.2 versions prior to 22.2R3; * 22.3 versions prior to 22.3R2.

CWE(s)

Related Threats

MITRE ATT&CK Enterprise Techniques

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.
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.
T1068 Exploitation for Privilege Escalation Privilege Escalation
Adversaries may exploit software vulnerabilities in an attempt to elevate privileges.
T1190 Exploit Public-Facing Application Initial Access
Adversaries may attempt to exploit a weakness in an Internet-facing host or system to initially access a network.
T1203 Exploitation for Client Execution Execution
Adversaries may exploit software vulnerabilities in client applications to execute code.
T1210 Exploitation of Remote Services Lateral Movement
Adversaries may exploit remote services to gain unauthorized access to internal systems once inside of a network.
Derived from this CVE’s CWE(s) via the direct CWE→ATT&CK cross-walk.

CVEs Like This One

CVE-2023-28959Same product: Juniper Junos
CVE-2024-39514Same product: Juniper Junos
CVE-2023-36849Same product: Juniper Junos
CVE-2024-21593Same product: Juniper Junos
CVE-2023-22413Same product: Juniper Junos
CVE-2023-36831Same product: Juniper Junos
CVE-2023-36842Same product: Juniper Junos
CVE-2023-28970Same product: Juniper Junos
CVE-2023-28965Same product: Juniper Junos
CVE-2025-30644Same product: Juniper Ex2300

Affected Assets

juniper
junos
20.4, 21.1, 21.2, 21.3, 21.4 · ≤ 20.4

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.

addresses: CWE-703

Implements explicit check and handling for the exceptional condition of audit logging process failure.

addresses: CWE-703

Establishing and monitoring system metrics with correlation and response actions helps identify and address improper handling of exceptional conditions.

addresses: CWE-703

Provides a defined response to detected conditions by restricting operation, ensuring exceptional conditions are handled rather than ignored or mishandled.

addresses: CWE-703

Contingency training equips users with defined procedures to check and respond to exceptional conditions during disruptions, reducing exploitation of mishandled errors.

addresses: CWE-703

Testing verifies the system's ability to detect, handle, and recover from exceptional conditions as part of the plan, reducing exploitability of improper exception handling.

addresses: CWE-703

Regular updates keep contingency procedures aligned with system changes, providing structured handling for exceptional conditions that would otherwise allow unmitigated exploitation.

addresses: CWE-703

Policy defines checks and handling for exceptional conditions arising from security incidents.

addresses: CWE-703

Performing IR tests ensures exceptional conditions are properly checked and handled to enable effective response.

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 explicitly require anticipating and correctly handling exceptional conditions during design and coding.

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.

none

Reporting of unhandled errors or exceptional conditions surfaces latent failure paths so they can be corrected before exploitation.

References