Security Resilience

CVE-2023-36849

Juniper Junos 21.4 … 22.3

Published
14 July 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 0.0030 21th percentile
Risk Priority 49 floored blend · peak EPSS

CVSS and EPSS are reproduced from their sources (NVD, FIRST EPSS). Risk Priority is our own derived reading, not an NVD score.

Summary

CVE-2023-36849 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, ranked at the 21th 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 Layer-2 control protocols daemon (l2cpd) of Juniper Networks Junos OS and Junos OS Evolved allows an unauthenticated adjacent attacker to cause a Denial of Service (DoS). When a malformed…

more

LLDP packet is received, l2cpd will crash and restart. The impact of the l2cpd crash is reinitialization of STP protocols (RSTP, MSTP or VSTP), and MVRP and ERP. Also, if any services depend on LLDP state (like PoE or VoIP device recognition), then these will also be affected. Continued receipt of such packets will lead to a sustained Denial of Service. This issue affects: Juniper Networks Junos OS 21.4 versions prior to 21.4R3-S3; 22.1 versions prior to 22.1R3-S3; 22.2 versions prior to 22.2R2-S1, 22.2R3; 22.3 versions prior to 22.3R2. Juniper Networks Junos OS Evolved 21.4-EVO versions prior to 21.4R3-S2-EVO; 22.1-EVO versions prior to 22.1R3-S3-EVO; 22.2-EVO versions prior to 22.2R2-S1-EVO, 22.2R3-EVO; 22.3-EVO versions prior to 22.3R2-EVO.

CWE(s)

Related Threats

CVEs Like This One

CVE-2024-39514Same product: Juniper Junos
CVE-2024-39552Same product: Juniper Junos
CVE-2025-60003Same product: Juniper Junos
CVE-2025-60004Same product: Juniper Junos
CVE-2023-36839Same product: Juniper Junos
CVE-2025-21597Same product: Juniper Junos
CVE-2025-60011Same product: Juniper Junos
CVE-2023-44178Same product: Juniper Junos
CVE-2024-21613Same product: Juniper Junos
CVE-2025-52949Same product: Juniper Junos

Affected Assets

juniper
junos
21.4, 22.1, 22.2, 22.3
juniper
junos os evolved
21.4, 22.1, 22.2, 22.3

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 (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.

removes

A.8.26 only requires that security requirements (including resilience against attacks like SQL injection) be identified and specified during development or acquisition; it does not itself remove, fix, or eliminate any exceptional-condition handling defects already present in code.

removes

A.8.28 mandates secure coding practices, principles, defect removal during coding/review, and prohibiting insecure techniques that directly produce improper exception handling; this removes most instances of the first-party code defect, with a bounded remainder in incomplete adoption or edge-case defects not captured by the baseline.

Hardening callouts derived

DISA STIG baselines are authored against specific weaknesses. Where this CVE cites a broad weakness class, the mapping is not asserted at that abstraction (owner ruling, 2026-09-25: grade only at Base and below), so no rule is shown here rather than a rule shown against the wrong grain.

  • No fine-grained STIG row for CWE-703, a pillar-level weakness, and none of its children carries one either.

References