CVE-2021-0208

Routing-service crash via malformed RSVP packet

Published Jan 15, 2021 · Updated Sep 16, 2024

Improper input validation in Juniper Networks Junos OS and Junos OS Evolved allows attackers to crash RPD via malformed RSVP packets. RPD accepts a malformed RSVP packet on an MPLS egress router without adequately validating it, causing the daemon to core. Bidirectional LSPs must be in use, and continued packet receipt sustains the routing-service outage.

CVSS severity8.8
High
EPSS probability0.65%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Improper input validation in Juniper Networks Junos OS and Junos OS Evolved allows attackers to crash RPD via malformed RSVP packets. RPD accepts a malformed RSVP packet on an MPLS egress router without adequately validating it, causing the daemon to core. Bidirectional LSPs must be in use, and continued packet receipt sustains the routing-service outage.

The record

CVE
CVE-2021-0208
Published
Jan 15, 2021
Updated
Sep 16, 2024
Vendor
Juniper Networks
Product
Junos OS Evolved
Classifications
CWE-20, T1499
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

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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=19.3 <19.3R2-S5-EVO
  2. Affected versionversion=19.4 <19.4R2-S2-EVO
  3. Affected versionversion=20.1 <20.1R1-S4-EVO

What conditions does exploitation require?

Attack vectoradjacent
Required privilegesunauthenticated

What is affected?

Juniper Networks · Junos OS Evolvedversion=19.3 <19.3R2-S5-EVO; version=19.4 <19.4R2-S2-EVO; version=20.1 <20.1R1-S4-EVO
Juniper Networks · Junos OSversion=15.1X49 <15.1X49-D240; version=17.4 <17.4R3-S2; version=18.1 <18.1R3-S10; version=18.2 <18.2R2-S7, 18.2R3-S4; version=18.3 <18.3R3-S2; version=18.4 <18.4R1-S8, 18.4R2-S6, 18.4R3-S2; version=19.1 <19.1R1-S5, 19.1R3-S3; version=19.2 <19.2R3; version=19.3 <19.3R2-S5, 19.3R3; version=19.4 <19.4R2-S2, 19.4R3-S1; version=20.1 <20.1R1-S4, 20.1R2; version=unspecified <17.3R3-S10

Published CVSS scores

3.3NIST NVDAV:A/AC:L/Au:N/C:N/I:N/A:P
8.8Juniper Networks, Inc.CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/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-20Improper Input Validation
T1499Endpoint Denial of Service

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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