CVE-2021-0206Network attack vector

PFE restart via SSL Proxy packet handling

Published Jan 15, 2021 · Updated Sep 17, 2024

NULL pointer dereference in Junos OS on affected NFX and SRX releases allows remote attackers to crash and restart the PFE. SSL Proxy packet handling dereferences a null pointer when it processes a specific crafted packet, although Juniper has not disclosed the packet structure or code locus. Only devices with the services ssl proxy configuration are exposed; repeated packets can keep the forwarding plane unavailable and sustain a service interruption.

CVSS severity7.5
High
EPSS probability1.31%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

NULL pointer dereference in Junos OS on affected NFX and SRX releases allows remote attackers to crash and restart the PFE. SSL Proxy packet handling dereferences a null pointer when it processes a specific crafted packet, although Juniper has not disclosed the packet structure or code locus. Only devices with the services ssl proxy configuration are exposed; repeated packets can keep the forwarding plane unavailable and sustain a service interruption.

The record

CVE
CVE-2021-0206
Published
Jan 15, 2021
Updated
Sep 17, 2024
Vendor
Juniper Networks
Product
Junos OS
Classifications
CWE-476, T1499.004
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jan 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

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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=18.3R1 <18.3* changes=[{"at":"18.3R3-S4","status":"unaffected"}]
  2. Affected versionversion=18.4 <18.4R3-S1
  3. Affected versionversion=19.1 <19.1R1-S6, 19.1R2-S2, 19.1R3
  4. Affected versionversion=19.2 <19.2R1-S2, 19.2R2
  5. Affected versionversion=19.3 <19.3R2

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Juniper Networks · Junos OSversion=18.3R1 <18.3* changes=[{"at":"18.3R3-S4","status":"unaffected"}]; version=18.4 <18.4R3-S1; version=19.1 <19.1R1-S6, 19.1R2-S2, 19.1R3; version=19.2 <19.2R1-S2, 19.2R2; version=19.3 <19.3R2

Published CVSS scores

7.5Juniper NetworksCVSS:3.1/AV:N/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)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-476NULL Pointer Dereference
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

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Your stack

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