CVE-2023-36849

Adjacent l2cpd crash via malformed LLDP packets

Published Jul 14, 2023 · Updated Oct 22, 2024

Improper exception handling in Juniper Networks Junos OS and Junos OS Evolved allows attackers to crash l2cpd via malformed LLDP packets. The Layer-2 control protocols daemon fails to handle a malformed LLDP packet, terminates, and then restarts. Access to the same Layer-2 segment is required, and repeated packets sustain the interruption while reinitializing STP, MVRP, and ERP and affecting LLDP-dependent services.

CVSS severity6.5
Medium
EPSS probability0.30%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Improper exception handling in Juniper Networks Junos OS and Junos OS Evolved allows attackers to crash l2cpd via malformed LLDP packets. The Layer-2 control protocols daemon fails to handle a malformed LLDP packet, terminates, and then restarts. Access to the same Layer-2 segment is required, and repeated packets sustain the interruption while reinitializing STP, MVRP, and ERP and affecting LLDP-dependent services.

The record

CVE
CVE-2023-36849
Published
Jul 14, 2023
Updated
Oct 22, 2024
Vendor
Juniper Networks
Product
Junos OS Evolved
Classifications
CWE-703, T1499
Attack vector
adjacent
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jul 14, 2023CVE publishedPublication date reported by the CVE source.
  2. Oct 22, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=21.4 <21.4R3-S2-EVO
  2. Affected versionversion=22.1 <22.1R3-S3-EVO
  3. Affected versionversion=22.2 <22.2R2-S1-EVO, 22.2R3-EVO
  4. Affected versionversion=22.3 <22.3R2-EVO

What conditions does exploitation require?

Attack vectoradjacent
Required privilegesunauthenticated

What is affected?

Juniper Networks · Junos OS Evolvedversion=21.4 <21.4R3-S2-EVO; version=22.1 <22.1R3-S3-EVO; version=22.2 <22.2R2-S1-EVO, 22.2R3-EVO; version=22.3 <22.3R2-EVO
Juniper Networks · Junos OSversion=21.4 <21.4R3-S3; version=22.1 <22.1R3-S3; version=22.2 <22.2R2-S1, 22.2R3; version=22.3 <22.3R2

Published CVSS scores

6.5Juniper NetworksCVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectoradjacent
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-703Improper Check or Handling of Exceptional Conditions
T1499Endpoint Denial of Service

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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