CVE-2024-21593

PFE crash via looping MPLS packet processing

Published Apr 12, 2024 · Updated Aug 1, 2024

Improper exception handling in the PFE of Juniper Networks Junos OS allows attackers to crash and restart MX routers via adjacent MPLS traffic. The PFE enters an internal loop while processing a specific MPLS packet, then crashes and restarts; repeated packets sustain the interruption. Exploitation requires no authentication but does require circuit cross-connect configuration and MPC10, MPC11, LC9600, or MX304 hardware.

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

See if you're affected

Explore vulnerability checks for your environment with Hinoki.

Book a demo

Summary

What happened

Improper exception handling in the PFE of Juniper Networks Junos OS allows attackers to crash and restart MX routers via adjacent MPLS traffic. The PFE enters an internal loop while processing a specific MPLS packet, then crashes and restarts; repeated packets sustain the interruption. Exploitation requires no authentication but does require circuit cross-connect configuration and MPC10, MPC11, LC9600, or MX304 hardware.

The record

CVE
CVE-2024-21593
Published
Apr 12, 2024
Updated
Aug 1, 2024
Vendor
Juniper Networks
Product
Junos OS
Classifications
CWE-703, T1498
Attack vector
adjacent
Privileges
unauthenticated

Timeline

How it unfolded

  1. Apr 12, 2024CVE publishedPublication date reported by the CVE source.
  2. Aug 1, 2024Record 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=21.4R3 <21.4R3-S5
  2. Affected versionversion=22.2R2 <22.2R3-S2
  3. Affected versionversion=22.3R1 <22.3R2-S2
  4. Affected versionversion=22.3R3 <22.3R3-S1
  5. Affected versionversion=22.4R1 <22.4R2-S2, 22.4R3
  6. Affected versionversion=23.2 <23.2R1-S1, 23.2R2

What conditions does exploitation require?

Attack vectoradjacent
Required privilegesunauthenticated

What is affected?

Juniper Networks · Junos OSversion=21.4R3 <21.4R3-S5; version=22.2R2 <22.2R3-S2; version=22.3R1 <22.3R2-S2; version=22.3R3 <22.3R3-S1; version=22.4R1 <22.4R2-S2, 22.4R3; version=23.2 <23.2R1-S1, 23.2R2

Published CVSS scores

6.5Juniper Networks, Inc.CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
7.1Juniper Networks, Inc.CVSS:4.0/AV:A/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:L

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-703Improper Check or Handling of Exceptional Conditions
T1498Network 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

See the directory against your own environment.

Your stack

Check the software in your environment

Book a demo to see how Hinoki identifies affected software and validates exploitability in your environment.

Book a demo