CVE-2021-0288

FPC crash via specific MPLS packet

Published Jul 15, 2021 · Updated Sep 17, 2024

Denial of service in Juniper Networks Junos OS on Trio-based MX and EX9200 devices allows attackers to crash an FPC via MPLS packets. The packet-forwarding engine's handling of a specific MPLS packet crashes the Modular Port Concentrator; Juniper publishes no deeper parser detail. An unauthenticated attacker must be adjacent to an affected Trio-based forwarding plane, and continued packet receipt sustains the service interruption.

CVSS severity6.5
Medium
EPSS probability0.38%
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

Denial of service in Juniper Networks Junos OS on Trio-based MX and EX9200 devices allows attackers to crash an FPC via MPLS packets. The packet-forwarding engine's handling of a specific MPLS packet crashes the Modular Port Concentrator; Juniper publishes no deeper parser detail. An unauthenticated attacker must be adjacent to an affected Trio-based forwarding plane, and continued packet receipt sustains the service interruption.

The record

CVE
CVE-2021-0288
Published
Jul 15, 2021
Updated
Sep 17, 2024
Vendor
Juniper Networks
Product
Junos OS
Classifications
CWE-754, T1499.004
Attack vector
adjacent
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jul 15, 2021CVE publishedPublication date reported by the CVE source.
  2. Sep 17, 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=17.3 <17.3R3-S12
  2. Affected versionversion=17.4 <17.4R2-S13, 17.4R3-S5
  3. Affected versionversion=18.1 <18.1R3-S13
  4. Affected versionversion=18.2 <18.2R3-S8
  5. Affected versionversion=18.3 <18.3R3-S5
  6. Affected versionversion=18.4 <18.4R2-S8, 18.4R3-S8
  7. Affected versionversion=19.1 <19.1R3-S5
  8. Affected versionversion=19.2 <19.2R3-S2
  9. Affected versionversion=19.3 <19.3R2-S6, 19.3R3-S3
  10. Affected versionversion=19.4 <19.4R1-S4, 19.4R1-S4, 19.4R2-S4, 19.4R3-S2
  11. Affected versionversion=20.1 <20.1R3
  12. Affected versionversion=20.2 <20.2R2-S2, 20.2R3
  13. Affected versionversion=20.3 <20.3R2
  14. Affected versionversion=20.4 <20.4R2

What conditions does exploitation require?

Attack vectoradjacent
Required privilegesunauthenticated

What is affected?

Juniper Networks · Junos OSversion=17.3 <17.3R3-S12; version=17.4 <17.4R2-S13, 17.4R3-S5; version=18.1 <18.1R3-S13; version=18.2 <18.2R3-S8; version=18.3 <18.3R3-S5; version=18.4 <18.4R2-S8, 18.4R3-S8; version=19.1 <19.1R3-S5; version=19.2 <19.2R3-S2; version=19.3 <19.3R2-S6, 19.3R3-S3; version=19.4 <19.4R1-S4, 19.4R1-S4, 19.4R2-S4, 19.4R3-S2; version=20.1 <20.1R3; version=20.2 <20.2R2-S2, 20.2R3; version=20.3 <20.3R2; version=20.4 <20.4R2

Published CVSS scores

3.3NIST NVDAV:A/AC:L/Au:N/C:N/I:N/A:P
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 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-754Improper Check for Unusual or Exceptional Conditions
T1499.004Application or System Exploitation

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