CVE-2021-0215

Packet-forwarding restart via 802.1X flap memory leak

Published Jan 15, 2021 · Updated Sep 16, 2024

Uncontrolled resource consumption in Junos OS allows attackers to restart packet forwarding through repeated 802.1X port flaps. Each flap of an interface configured as an 802.1X authenticator leaks memory instead of releasing it, eventually destabilizing pfex and other processes. The dot1x configuration is required, and repeated local-network interface state changes can interrupt forwarding without exposing or modifying data.

CVSS severity6.5
Medium
EPSS probability0.79%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Uncontrolled resource consumption in Junos OS allows attackers to restart packet forwarding through repeated 802.1X port flaps. Each flap of an interface configured as an 802.1X authenticator leaks memory instead of releasing it, eventually destabilizing pfex and other processes. The dot1x configuration is required, and repeated local-network interface state changes can interrupt forwarding without exposing or modifying data.

The record

CVE
CVE-2021-0215
Published
Jan 15, 2021
Updated
Sep 16, 2024
Vendor
Juniper Networks
Product
Junos OS
Classifications
CWE-400, T1499.004
Attack vector
adjacent
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jan 15, 2021CVE publishedPublication date reported by the CVE source.
  2. Sep 16, 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=14.1X53 <14.1X53-D54
  2. Affected versionversion=15.1X49 <15.1X49-D240
  3. Affected versionversion=15.1X53 <15.1X53-D593
  4. Affected versionversion=16.1 <16.1R7-S8
  5. Affected versionversion=17.2 <17.2R3-S4
  6. Affected versionversion=17.3 <17.3R3-S8
  7. Affected versionversion=17.4 <17.4R2-S11, 17.4R3-S2
  8. Affected versionversion=18.1 <18.1R3-S10
  9. Affected versionversion=18.2 <18.2R2-S7, 18.2R3-S3
  10. Affected versionversion=18.3 <18.3R2-S4, 18.3R3-S2
  11. Affected versionversion=18.4 <18.4R1-S7, 18.4R2-S4, 18.4R3-S2
  12. Affected versionversion=19.1 <19.1R1-S5, 19.1R2-S2, 19.1R3
  13. Affected versionversion=19.2 <19.2R1-S5, 19.2R2
  14. Affected versionversion=19.3 <19.3R2-S3, 19.3R3
  15. Affected versionversion=19.4 <19.4R1-S2, 19.4R2

What conditions does exploitation require?

Attack vectoradjacent
Required privilegesunauthenticated

What is affected?

Juniper Networks · Junos OSversion=14.1X53 <14.1X53-D54; version=15.1X49 <15.1X49-D240; version=15.1X53 <15.1X53-D593; version=16.1 <16.1R7-S8; version=17.2 <17.2R3-S4; version=17.3 <17.3R3-S8; version=17.4 <17.4R2-S11, 17.4R3-S2; version=18.1 <18.1R3-S10; version=18.2 <18.2R2-S7, 18.2R3-S3; version=18.3 <18.3R2-S4, 18.3R3-S2; version=18.4 <18.4R1-S7, 18.4R2-S4, 18.4R3-S2; version=19.1 <19.1R1-S5, 19.1R2-S2, 19.1R3; version=19.2 <19.2R1-S5, 19.2R2; version=19.3 <19.3R2-S3, 19.3R3; version=19.4 <19.4R1-S2, 19.4R2

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.

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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-400Uncontrolled Resource Consumption
T1499.004Application or System Exploitation

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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