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No exploitation reported

CVE-2021-0211

No exploitation reported by the sources we read.

  • Published2021-01-15
  • WeaknessCWE-754

Am I affected?

With a domain, we read the version its public headers and pages expose. A distribution build can carry the fix under an older number.

Description

An improper check for unusual or exceptional conditions in Juniper Networks Junos OS and Junos OS Evolved Routing Protocol Daemon (RPD) service allows an attacker to send a valid BGP FlowSpec message thereby causing an unexpected change in the route advertisements within the BGP FlowSpec domain leading to disruptions in network traffic causing a Denial of Service (DoS) condition. Continued receipt of these update messages will cause a sustained Denial of Service condition. This issue affects Juniper Networks: Junos OS: All versions prior to 17.3R3-S10 with the exceptions of 15.1X49-D240 on SRX Series and 15.1R7-S8 on EX Series; 17.3 versions prior to 17.3R3-S10; 17.4 versions prior to 17.4R2-S12, 17.4R3-S4; 18.1 versions prior to 18.1R3-S12; 18.2 versions prior to 18.2R2-S8, 18.2R3-S6; 18.3 versions prior to 18.3R3-S4; 18.4 versions prior to 18.4R1-S8, 18.4R2-S6, 18.4R3-S6; 19.1 versions prior to 19.1R1-S6, 19.1R2-S2, 19.1R3-S3; 19.2 versions prior to 19.2R3-S1; 19.3 versions prior to 19.3R2-S5, 19.3R3-S1; 19.4 versions prior to 19.4R1-S3, 19.4R2-S3, 19.4R3; 20.1 versions prior to 20.1R2; 20.2 versions prior to 20.2R1-S3 20.2R2; 20.3 versions prior to 20.3R1-S1, 20.3R2. Junos OS Evolved: All versions prior to 20.3R1-S1-EVO, 20.3R2-EVO.

Timeline

dates in UTC
  1. 2021-01-1518:15CVE publishedNVD

Observed activity

isMalicious corpus · updated 2026-10-23 18:48 UTC
Indicators tagged with this CVE, per day0 indicators over 7 days
Block these indicators
  • Firewall list (EDL, text): https://api.ismalicious.com/edl/cve/CVE-2021-0211?format=txt
  • CSV export: https://api.ismalicious.com/edl/cve/CVE-2021-0211?format=csv
  • TAXII collection of exploited CVEs
  • The EDL and CSV take an API key on the Pro plan.

Versions per branch

NVD
Juniper junosversion to verify
BranchAffectedFixed in
17.3= 17.3no fix published
17.4= 17.4no fix published
18.1= 18.1no fix published
18.2= 18.2no fix published
18.3= 18.3no fix published
18.4= 18.4no fix published
19.1= 19.1no fix published
19.2= 19.2no fix published
19.3= 19.3no fix published
19.4= 19.4no fix published
20.1= 20.1no fix published
20.2= 20.2no fix published
Juniper junos os evolved
BranchAffectedFixed in
19.2= 19.2no fix published
19.3= 19.3no fix published
19.4= 19.4no fix published
20.1= 20.1no fix published
20.2= 20.2no fix published
20.3= 20.3no fix published

as publishedRanges as NVD and OSV publish them; a distribution’s build can be fixed under an older number.

Fix

Advisories and patches

Detection

Nuclei template
none so far
ProjectDiscovery
Exploit-DB
no entry
Exploit-DB
Proof-of-concept repositories
none listed
PoC-in-GitHub

Sources

  • CNACVSS 3.110read 2026-10-23
  • NVDCVSS 2.06.4read 2026-10-23
  • NVDweakness (CWE)CWE-754read 2026-10-23
  • FIRST EPSSEPSS score1.3 %2026-10-22

Technical details

CVSS v3 Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:H/A:H
Published
2021-01-15
Last Modified
2026-06-17
NVD status
Modified

Frequently asked questions

What is CVE-2021-0211?

An improper check for unusual or exceptional conditions in Juniper Networks Junos OS and Junos OS Evolved Routing Protocol Daemon (RPD) service allows an attacker to send a valid BGP FlowSpec message thereby causing an unexpected change in the route advertisements within the BGP FlowSpec domain leading to disruptions in network traffic causing a Denial of Service (DoS) condition. Continued receipt of these update messages will cause a sustained Denial of Service condition. This issue affects Juniper Networks: Junos OS: All versions prior to 17.3R3-S10 with the exceptions of 15.1X49-D240 on SRX Series and 15.1R7-S8 on EX Series; 17.3 versions prior to 17.3R3-S10; 17.4 versions prior to 17.4R2-S12, 17.4R3-S4; 18.1 versions prior to 18.1R3-S12; 18.2 versions prior to 18.2R2-S8, 18.2R3-S6; 18.3 versions prior to 18.3R3-S4; 18.4 versions prior to 18.4R1-S8, 18.4R2-S6, 18.4R3-S6; 19.1 versions prior to 19.1R1-S6, 19.1R2-S2, 19.1R3-S3; 19.2 versions prior to 19.2R3-S1; 19.3 versions prior to 19.3R2-S5, 19.3R3-S1; 19.4 versions prior to 19.4R1-S3, 19.4R2-S3, 19.4R3; 20.1 versions prior to 20.1R2; 20.2 versions prior to 20.2R1-S3 20.2R2; 20.3 versions prior to 20.3R1-S1, 20.3R2. Junos OS Evolved: All versions prior to 20.3R1-S1-EVO, 20.3R2-EVO.

Is CVE-2021-0211 actively exploited?

Active exploitation of CVE-2021-0211 has not been confirmed. Its EPSS score was 1.3% on 2026-10-22, the estimated probability of exploitation in the next 30 days.

What is the CVSS score for CVE-2021-0211?

CVE-2021-0211 has a CVSS v3 base score of 10 (CRITICAL severity), with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:H/A:H.

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