CVE-2023-36842

Adjacent service hang via DHCP packet loop

Published Jan 12, 2024 · Updated Jun 17, 2025

Improper condition handling in Juniper Networks Junos OS allows adjacent attackers to hang jdhcpd with a crafted DHCP packet. With forward-snooped-client configured, jdhcpd enters an infinite loop when a specific DHCP packet arrives on an unconfigured interface, consuming all CPU cycles. Exploitation requires adjacent-network access to an MX or EX device in that configuration and interrupts DHCP service while the daemon remains hung.

CVSS severity6.5
Medium
EPSS probability0.29%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Improper condition handling in Juniper Networks Junos OS allows adjacent attackers to hang jdhcpd with a crafted DHCP packet. With forward-snooped-client configured, jdhcpd enters an infinite loop when a specific DHCP packet arrives on an unconfigured interface, consuming all CPU cycles. Exploitation requires adjacent-network access to an MX or EX device in that configuration and interrupts DHCP service while the daemon remains hung.

The record

CVE
CVE-2023-36842
Published
Jan 12, 2024
Updated
Jun 17, 2025
Vendor
Juniper Networks
Product
Junos OS
Classifications
CWE-755, CWE-703, T1499
Attack vector
adjacent
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jan 12, 2024CVE publishedPublication date reported by the CVE source.
  2. Jun 17, 2025Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

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

  1. Affected versionversion=0 <20.4R3-S9
  2. Affected versionversion=21.2 <21.2R3-S7
  3. Affected versionversion=21.3 <21.3R3-S5
  4. Affected versionversion=21.4 <21.4R3-S5
  5. Affected versionversion=22.1 <22.1R3-S4
  6. Affected versionversion=22.2 <22.2R3-S3
  7. Affected versionversion=22.3 <22.3R3-S2
  8. Affected versionversion=22.4 <22.4R2-S2, 22.4R3
  9. Affected versionversion=23.2 <23.2R2

What conditions does exploitation require?

Attack vectoradjacent
Required privilegesunauthenticated

What is affected?

Juniper Networks · Junos OSversion=0 <20.4R3-S9; version=21.2 <21.2R3-S7; version=21.3 <21.3R3-S5; version=21.4 <21.4R3-S5; version=22.1 <22.1R3-S4; version=22.2 <22.2R3-S3; version=22.3 <22.3R3-S2; version=22.4 <22.4R2-S2, 22.4R3; version=23.2 <23.2R2

Published CVSS scores

6.5Juniper NetworksCVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
6.5NIST NVDCVSS: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 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectoradjacent
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-755Improper Handling of Exceptional Conditions
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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