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CVE-2021-0211

31
FAUCET Score

CVE-2021-0211 is a critical denial-of-service vulnerability affecting Juniper Networks Junos OS and Junos OS Evolved. An attacker can exploit an improper check in the Routing Protocol Daemon (RPD) service by sending a crafted BGP FlowSpec message, leading to unexpected route changes and network traffic disruptions. This vulnerability has a CVSS score of 10.0 (Critical), indicating it can be exploited remotely with low complexity and high impact on availability and integrity. While no active exploitation or public exploit code has been identified, and community discussion is minimal, the potential for a sustained denial of service makes this a significant risk.

Impacted Technologies

VendorProductVersion(s)CPE
17.3CPE matchmatch criteria
cpe:2.3:o:juniper:junos:17.3:-:*:*:*:*:*:*
17.3CPE matchmatch criteria
cpe:2.3:o:juniper:junos:17.3:r1-s1:*:*:*:*:*:*
17.3CPE matchmatch criteria
cpe:2.3:o:juniper:junos:17.3:r2:*:*:*:*:*:*
17.3CPE matchmatch criteria
cpe:2.3:o:juniper:junos:17.3:r2-s1:*:*:*:*:*:*
17.3CPE matchmatch criteria
cpe:2.3:o:juniper:junos:17.3:r2-s2:*:*:*:*:*:*

CVSS Data

CVSS version used by this source: 3.1

10.0CRITICAL

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:H/A:H

Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
NONE
User Interaction
NONE
Scope
CHANGED
Confidentiality Impact
NONE
Integrity Impact
HIGH
Availability Impact
HIGH
Exploitability Score
3.9
Impact Score
5.8
CvssVersion
3.1

Exploit Intelligence

EPSS Score
1.32%
Probability of exploitation in next 30 days
EPSS Percentile
67.8%
Percentile rank of EPSS score among Peer Group
As of 2026-07-27
Model: v2026.06.15
This CVE's current EPSS score of 0.0132 is in the 54th percentile among its peer group of 36,897 CVEs.

Social Chatter

The average CVE in this peer group has 0.0 Twitter, 0.1 Reddit, 0.3 Bluesky, 0.3 Mastodon, and 2.4 GitHub mentions.

Media Mentions

No media coverage found for this CVE.

The average CVE in this peer group has 0.3 InfoSec Media, 0.0 Vendor Blog, and 0.0 Security Researcher mentions.

Remediation

Vendor Patches (1)

junipervendor investigatingvia nvd_reference
View patch

References

kb.juniper.net / JSA11101
Vendor Advisory