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CVE-2021-31353

HIGHCVSS 7.5/10EPSS 1.13%

Last modified

CVE-2021-31353 is a high-severity vulnerability rated 7.5/10 on the CVSS scale. An Improper Handling of Exceptional Conditions vulnerability in Juniper Networks Junos OS and Junos OS Evolved allows an attacker to inject a specific BGP update, causing the routing protocol daemon (RPD) to crash and restart, leading to a Denial of Service (DoS). Continued receipt and processing of the BGP update will create a sustained Denial of Service (DoS) condition. EPSS estimates a 1.13% chance of exploitation in the next 30 days.

Description

An Improper Handling of Exceptional Conditions vulnerability in Juniper Networks Junos OS and Junos OS Evolved allows an attacker to inject a specific BGP update, causing the routing protocol daemon (RPD) to crash and restart, leading to a Denial of Service (DoS). Continued receipt and processing of the BGP update will create a sustained Denial of Service (DoS) condition. This issue affects very specific versions of Juniper Networks Junos OS: 19.3R3-S2; 19.4R3-S3; 20.2 versions 20.2R2-S3 and later, prior to 20.2R3-S2; 20.3 versions 20.3R2 and later, prior to 20.3R3; 20.4 versions 20.4R2 and later, prior to 20.4R3; 21.1 versions prior to 21.1R2. Juniper Networks Junos OS 20.1 is not affected by this issue. This issue also affects Juniper Networks Junos OS Evolved: All versions prior to 20.4R2-S3-EVO, 20.4R3-EVO; 21.1-EVO versions prior to 21.1R2-EVO; 21.2-EVO versions prior to 21.2R2-EVO.

Metrics

CVSS 3.1
7.5/10

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

EPSS Probability
1.13%

62.3th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

Affected Software

VendorProductVersionsUpdate
JuniperJunos19.3R3-S2
JuniperJunos19.4R3-S3
JuniperJunos20.2R2-S3
JuniperJunos20.3R2
JuniperJunos20.4R2
JuniperJunos21.1R1
JuniperJunos Os Evolved<= 20.3—
JuniperJunos Os Evolved20.4R1
JuniperJunos Os Evolved21.1R1
JuniperJunos Os Evolved21.2R1

References

Timeline

Published
Last Modified
Status
Modified

Frequently Asked Questions

What is CVE-2021-31353?
An Improper Handling of Exceptional Conditions vulnerability in Juniper Networks Junos OS and Junos OS Evolved allows an attacker to inject a specific BGP update, causing the routing protocol daemon (RPD) to crash and restart, leading to a Denial of Service (DoS). Continued receipt and processing of the BGP update will create a sustained Denial of Service (DoS) condition. This issue affects very specific versions of Juniper Networks Junos OS: 19.3R3-S2; 19.4R3-S3; 20.2 versions 20.2R2-S3 and later, prior to 20.2R3-S2; 20.3 versions 20.3R2 and later, prior to 20.3R3; 20.4 versions 20.4R2 and later, prior to 20.4R3; 21.1 versions prior to 21.1R2. Juniper Networks Junos OS 20.1 is not affected by this issue. This issue also affects Juniper Networks Junos OS Evolved: All versions prior to 20.4R2-S3-EVO, 20.4R3-EVO; 21.1-EVO versions prior to 21.1R2-EVO; 21.2-EVO versions prior to 21.2R2-EVO.
How severe is CVE-2021-31353?
CVE-2021-31353 has a CVSS score of 7.5/10 (HIGH severity). The EPSS model estimates a 1.13% probability of exploitation in the next 30 days.
How do I fix CVE-2021-31353?
Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2021-31353?

Run a free Strix scan to check your systems for this vulnerability.

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Source: NVD / NIST