CVE-2021-0287 json
Junos OS and Junos OS Evolved: RPD could crash in SR-ISIS/MPLS environment due to a flap of an ISIS link in the network
published 2021-07-15 5 y ago modified 2026-06-17 4 mo ago also EUVD-2021-2906
- cvss
- 6.5
- version 3.1, CNA
- cisa kev
- Not listed
- not in CISA's catalog
- epss
- 0.4%
- EPSS 0.4% chance of exploitation in 30 days, percentile 31%
- public exploits
- 0
- none known
Summary
In a Segment Routing ISIS (SR-ISIS)/MPLS environment, on Juniper Networks Junos OS and Junos OS Evolved devices, configured with ISIS Flexible Algorithm for Segment Routing and sensor-based statistics, a flap of a ISIS link in the network, can lead to a routing process daemon (RPD) crash and restart, causing a Denial of Service (DoS). Continued link flaps will create a sustained Denial of Service (DoS) condition. This issue affects: Juniper Networks Junos OS: 19.4 versions prior to 19.4R1-S4, 19.4R3-S2; 20.1 versions prior to 20.1R2-S1, 20.1R3; 20.2 versions prior to 20.2R2-S2, 20.2R3; 20.3 versions prior to 20.3R2; Juniper Networks Junos OS Evolved: 20.3-EVO versions prior to 20.3R2-EVO; 20.4-EVO versions prior to 20.4R2-EVO. This issue does not affect: Juniper Networks Junos OS releases prior to 19.4R1. Juniper Networks Junos OS Evolved releases prior to 19.4R1-EVO.
Patch / fix
- Juniper Networks Junos OS 19.4R1-S4, 19.4R3-S2, 20.1R2-S1, 20.1R3, 20.2R2-S2, 20.2R3, 20.3R2
- Juniper Networks Junos OS Evolved 20.3R2-EVO, 20.4R2-EVO
Exploit prediction
0.37% chance of exploitation in the next 30 days, higher than 31% of all scored CVEs (FIRST EPSS, 2026-11-08).
CVSS scores
| assigned by | version | score | vector |
|---|---|---|---|
| CNA | 3.1 | 6.5 | CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H |
| NVD | 2.0 | 5.7 | AV:A/AC:M/Au:N/C:N/I:N/A:C |
Affected products
- Juniper Networks Junos OS
- Juniper Networks Junos OS Evolved
Classification
- Weakness
-
- CWE-754 Improper Check for Unusual or Exceptional Conditions
References
-
kb.juniper.net
/JSA11189
vendor-advisory
Sources
- CVE List CVE-2021-0287
- NVD CVE-2021-0287
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