Security Resilience

CVE-2023-36839

Juniper Junos ≤ 20.4

Published
12 October 2023
Modified
21 November 2024
Patch / advisory
View 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-2023-36839 is a medium-severity Improper Validation of Specified Quantity in Input (CWE-1284) vulnerability in Juniper Junos. Its CVSS base score is 6.5 (Medium).

Operationally, exploitation aligns with the MITRE ATT&CK technique OS Credential Dumping (T1003); ranked at the 21th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.

EU & UK References

Vulnerability Data

An Improper Validation of Specified Quantity in Input vulnerability in the Layer-2 control protocols daemon (l2cpd) of Juniper Networks Junos OS and Junos OS Evolved allows an unauthenticated adjacent attacker who sends specific LLDP packets to cause a Denial of…

more

Service(DoS). This issue occurs when specific LLDP packets are received and telemetry polling is being done on the device. 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. This issue affects: Juniper Networks Junos OS * All versions prior to 20.4R3-S8; * 21.1 version 21.1R1 and later versions; * 21.2 versions prior to 21.2R3-S5; * 21.3 versions prior to 21.3R3-S4; * 21.4 versions prior to 21.4R3-S3; * 22.1 versions prior to 22.1R3-S2; * 22.2 versions prior to 22.2R3; * 22.3 versions prior to 22.3R2-S2; * 22.4 versions prior to 22.4R2; Juniper Networks Junos OS Evolved * All versions prior to 20.4R3-S8-EVO; * 21.1 version 21.1R1-EVO and later versions; * 21.2 versions prior to 21.2R3-S5-EVO; * 21.3 versions prior to 21.3R3-S4-EVO; * 21.4 versions prior to 21.4R3-S3-EVO; * 22.1 versions prior to 22.1R3-S2-EVO; * 22.2 versions prior to 22.2R3-EVO; * 22.3 versions prior to 22.3R2-S2-EVO; * 22.4 versions prior to 22.4R1-S1-EVO;

CWE(s)
CWE-1284

Related Threats

MITRE ATT&CK Enterprise Techniques

T1003 OS Credential Dumping Credential Access
Adversaries may attempt to dump credentials to obtain account login and credential material, normally in the form of a hash or a clear text password.
attack.mitre.org →
T1003.001 LSASS Memory Credential Access
Adversaries may attempt to access credential material stored in the process memory of the Local Security Authority Subsystem Service (LSASS).
attack.mitre.org →
T1003.002 Security Account Manager Credential Access
Adversaries may attempt to extract credential material from the Security Account Manager (SAM) database either through in-memory techniques or through the Windows Registry where the SAM database is stored.
attack.mitre.org →
T1003.003 NTDS Credential Access
Adversaries may attempt to access or create a copy of the Active Directory domain database in order to steal credential information, as well as obtain other information about domain members such as devices, users, and access rights.
attack.mitre.org →
T1003.004 LSA Secrets Credential Access
Adversaries with SYSTEM access to a host may attempt to access Local Security Authority (LSA) secrets, which can contain a variety of different credential materials, such as credentials for service accounts.
attack.mitre.org →
T1006 Direct Volume Access Stealth
Adversaries may directly access a volume to bypass file access controls and file system monitoring.
attack.mitre.org →
Derived from this CVE’s CWE(s) via the direct CWE→ATT&CK cross-walk.

CVEs Like This One

CVE-2026-21908Same product: Juniper Junos
CVE-2025-30646Same product: Juniper Junos
CVE-2025-52946Same product: Juniper Junos
CVE-2024-30395Same product: Juniper Junos
CVE-2024-39558Same product: Juniper Junos
CVE-2025-59959Same product: Juniper Junos
CVE-2024-39543Same product: Juniper Junos
CVE-2025-30653Same product: Juniper Junos
CVE-2023-44182Same product: Juniper Junos
CVE-2024-39528Same product: Juniper Junos

Affected Assets

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

Mitigating Controls

Control response

Prevent
Stop it (NIST 800-53)

—

Detect
Catch it (NIST detect / respond)

—

Harden
Shrink the surface (DISA STIG)

—

Validate
Prove the fix (OWASP ASVS)
  • V6.7.2
  • V1.4.2
  • V2.2.1
  • V2.2.2

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 partial match
blocks

Secure SDLC practices directly require proper quantity/length validation in input handling.

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.5.14 Information transfer partial match
removes
A.5.15 Access control partial match
removes
A.5.16 Identity management partial match
removes
A.5.17 Authentication information partial match
removes
A.5.18 Access rights partial match
removes
A.8.10 Information deletion partial match
removes

References