An Improper Check for Unusual or Exceptional Conditions vulnerability in the kernel of Juniper Networks Junos OS allows an adjacent unauthenticated attacker to bypass an integrity check.

In a 6PE scenario and if an additional integrity check is configured, it will fail to drop specific malformed IPv6 packets, and then these packets will be forwarded to other connected networks.

This issue affects Juniper Networks Junos OS:

All versions prior to 19.3R3-S7;

19.4 versions prior to 19.4R3-S9;

20.2 versions prior to 20.2R3-S7;

20.3 versions prior to 20.3R3-S5;

20.4 versions prior to 20.4R3-S4;

21.1 versions prior to 21.1R3-S3;

21.2 versions prior to 21.2R3-S2;

21.3 versions prior to 21.3R3-S1;

21.4 versions prior to 21.4R2-S1, 21.4R3;

22.1 versions prior to 22.1R2;

22.2 versions prior to 22.2R2.

For a system to be affected it would need to be configured for 6PE where the following command is required:

Juniper SIRT is not aware of any malicious exploitation of this vulnerability.

This issue was seen during production usage.

This issue has been assigned CVE-2023-28979.

The following software releases have been updated to resolve this specific issue: 19.3R3-S7, 19.4R3-S9, 20.2R3-S7, 20.3R3-S5, 20.4R3-S4, 21.1R3-S3, 21.2R3-S2, 21.3R3-S1, 21.4R2-S1, 21.4R3, 22.1R2, 22.2R2, 22.3R1, and all subsequent releases.

This issue is being tracked as 1662400

Note: Juniper SIRT's policy is not to evaluate releases which are beyond End of Engineering (EOE) or End of Life (EOL).

• 2023-04-12: Initial Publication.

• KB16613: Overview of the Juniper Networks SIRT Quarterly Security Bulletin Publication Process [juniper.net]
• KB16765: In which releases are vulnerabilities fixed? [juniper.net]
• KB16446: Common Vulnerability Scoring System (CVSS) and Juniper's Security Advisories [juniper.net]
• Report a Security Vulnerability - How to Contact the Juniper Networks Security Incident Response Team
• CVE-2023-28979 at cve.mitre.org