CVE-2021-0272

Service interruption via FPC kernel memory exhaustion

Published Apr 22, 2021 · Updated Sep 17, 2024

Kernel memory exhaustion in Juniper Networks Junos OS on specified QFX10000 switches allows adjacent attackers to interrupt service. In EVPN-VXLAN scenarios, Flexible PIC Concentrators fail to release kernel memory while processing specific genuine packets destined to the device. Repeated traffic crashes and restarts QFX10002 devices or crashes QFX10008 and QFX10016 FPCs until traffic stops, and a device reboot is required to restore service.

CVSS severity6.5
Medium
EPSS probability0.42%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Kernel memory exhaustion in Juniper Networks Junos OS on specified QFX10000 switches allows adjacent attackers to interrupt service. In EVPN-VXLAN scenarios, Flexible PIC Concentrators fail to release kernel memory while processing specific genuine packets destined to the device. Repeated traffic crashes and restarts QFX10002 devices or crashes QFX10008 and QFX10016 FPCs until traffic stops, and a device reboot is required to restore service.

The record

CVE
CVE-2021-0272
Published
Apr 22, 2021
Updated
Sep 17, 2024
Vendor
Juniper Networks
Product
Junos OS
Classifications
CWE-401, T1499.001
Attack vector
adjacent
Privileges
unauthenticated

Timeline

How it unfolded

  1. Apr 22, 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

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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=16.1R1 <16.1*
  2. Affected versionversion=17.3 <17.3R3-S9
  3. Affected versionversion=17.4 <17.4R3-S2
  4. Affected versionversion=18.1 <18.1R3-S11
  5. Affected versionversion=18.2 <18.2R3-S5
  6. Affected versionversion=18.3 <18.3R3-S3
  7. Affected versionversion=18.4 <18.4R2-S5, 18.4R3-S4
  8. Affected versionversion=19.1 <19.1R3-S2
  9. Affected versionversion=19.2 <19.2R3
  10. Affected versionversion=19.3 <19.3R3
  11. Affected versionversion=19.4 <19.4R3
  12. Affected versionversion=20.1 <20.1R2

What conditions does exploitation require?

Attack vectoradjacent
Required privilegesunauthenticated

What is affected?

Juniper Networks · Junos OSversion=16.1R1 <16.1*; version=17.3 <17.3R3-S9; version=17.4 <17.4R3-S2; version=18.1 <18.1R3-S11; version=18.2 <18.2R3-S5; version=18.3 <18.3R3-S3; version=18.4 <18.4R2-S5, 18.4R3-S4; version=19.1 <19.1R3-S2; version=19.2 <19.2R3; version=19.3 <19.3R3; version=19.4 <19.4R3; version=20.1 <20.1R2

Published CVSS scores

6.5Juniper NetworksCVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
6.1NIST NVDAV:A/AC:L/Au:N/C:N/I:N/A:C

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.

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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-401Missing Release of Memory after Effective Lifetime
T1499.001OS Exhaustion Flood

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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