CVE-2021-0209

Junos OS Evolved: Receipt of certain valid BGP update packets from BGP peers may cause RPD to core when using REGEX.

MEDIUM
6.5
CVSS Score
Published: January 15, 2021 at 05:35 PM UTC
Updated: June 17, 2026 at 03:29 AM UTC
2 products affected across 2 vendorsJunos OS EvolvedJunos OS Evolved

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Severity
MEDIUM6.5
Exploit prediction
EPSS 0.4%

Description

In Juniper Networks Junos OS Evolved an attacker sending certain valid BGP update packets may cause Junos OS Evolved to access an uninitialized pointer causing RPD to core leading to a Denial of Service (DoS). Continued receipt of these types of valid BGP update packets will cause an extended Denial of Service condition. RPD will require a restart to recover. An indicator of compromise is to see if the file rpd.re exists by issuing the command: show system core-dumps This issue affects: Juniper Networks Junos OS Evolved 19.4 versions prior to 19.4R2-S2-EVO; 20.1 versions prior to 20.1R1-S2-EVO, 20.1R2-S1-EVO. This issue does not affect Junos OS.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

19.4 ≤ v < 19.4R2-S2-EVO20.1 ≤ v < 20.1R1-S2-EVO, 20.1R2-S1-EVO19.420.1
Affected range stops below 19.4R2-S2-EVO, so it looks safe — our inference, not a vendor statement
Affected range stops below 20.1R1-S2-EVO, 20.1R2-S1-EVO, so it looks safe — our inference, not a vendor statement

Remediation

No guide yet

No remediation guidance has been written for this CVE yet. What the record does show:

Patch and advisory references

References (1)

x_refsource_CONFIRMVendor Advisory
https://kb.juniper.net/JSA11099

CVSS

6.5MEDIUMjuniper
Attack Vector
ADJACENT_NETWORK
Complexity
LOW
Privileges
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
NONE
Integrity
NONE
Availability
HIGH
Vector?

Quick Info

StatusMODIFIED
CWE
CWE-824

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