01 Record

CVE-2021-31362

Junos OS and Junos OS Evolved: An IS-IS adjacency might be taken down if a bad hello PDU is received for an existing adjacency causing a DoS

MediumPUBLISHEDCNA: juniper

CNA base score6.5 CVSS v3.xCVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

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02 Description

Junos OS and Junos OS Evolved: An IS-IS adjacency might be taken down if a bad hello PDU is received for an existing adjacency causing a DoS

03 Exploitation and scoring

Exploitation: Not assessed. CISA has not published an exploitation assessment for this record, and it is not in the KEV catalog. That is an absence of assessment, not a finding of no risk.
SSVC decision: Not assessed by CISA
EPSS probability: 0.42% probability of exploitation activity in the next 30 days.
EPSS percentile: Equal to or higher than the score of 36.2% of scored records. A rank, not a probability.
NVD base score: 6.5 (CVSS v3.x), scored by the NVD independently of the CNA.
NVD CVSS vector: CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
NVD analysis status: Modified. NVD last modified this record on 2026-06-17.
Red Hat severity: No Red Hat rating. Red Hat rates the CVEs that affect its products.

Exploit-prediction scores from FIRST. Independent scoring and analysis status from the NVD. Vendor severity from Red Hat. Exploitation assessment and catalog membership from CISA.

04 Metadata

Published

2021-10-19 18:16Z5 YR AGO

Last updated

2024-09-17 00:15Z2 YR AGO

Reserved

2021-04-15

Assigning CNA

juniper

Record state

PUBLISHED

Severity

Medium (CVSS 6.5)

CNA CVSS vector

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

Weaknesses

CWE-693Protection Mechanism FailurePillar

Data version

5.1

Document digest

708a0162f4eecb9145f521964ea78d601930b8ee8f6f65be523b45bf84fb2efb

05 Affected products

VendorProductVersionsPlatforms

Juniper NetworksJunos OS< 18.2R3-S8, 18.3 to < 18.3R3-S5, 18.4 to < 18.4R3-S9, 19.1 to < 19.1R3-S7, 19.2 to < 19.2R1-S7, 19.2R3-S3, 19.3 to < 19.3R2-S6, 19.3R3-S2, 19.4 to < 19.4R3-S3, 20.1 to < 20.1R3, 20.2 to < 20.2R3, 20.3 to < 20.3R3, 20.4 to < 20.4R2—

Juniper NetworksJunos OS Evolved< 20.4R2-EVO, 21.1 to < 21.1R2-EVO—

06 References

kb.juniper.nethttps://kb.juniper.net/JSA11224x_refsource_CONFIRM

07 Remediation

The following software releases have been updated to resolve this specific issue in JUNOS OS: 18.2R3-S8, 18.3R3-S5, 18.4R3-S9, 19.1R3-S7, 19.2R1-S7, 19.2R3-S3, 19.3R2-S6, 19.3R3-S2, 19.4R3-S3, 20.1R3, 20.2R3, 20.3R3, 20.4R2, 21.1R1, and all subsequent releases. The following software releases have been updated to resolve this specific issue in JUNOS OS Evolved: 20.4R2-EVO, 21.1R2-EVO, 21.2R1-EVO, and all subsequent releases.