CVE-2024-21617: Junos OS: BGP flap on NSR-enabled devices causes memory leak

Severity: medium (CVSS 6.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.3% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2024-01-12 · updated 2026-06-17
Weakness: CWE-459

Description

An Incomplete Cleanup vulnerability in Nonstop active routing (NSR) component of Juniper Networks Junos OS allows an adjacent, unauthenticated attacker to cause memory leak leading to Denial of Service (DoS). On all Junos OS platforms, when NSR is enabled, a BGP flap will cause memory leak. A manual reboot of the system will restore the services. Note: NSR is not supported on the SRX Series and is therefore not affected by this vulnerability. The memory usage can be monitored using the below commands. user@host> show chassis routing-engine no-forwarding user@host> show system memory | no-more This issue affects: Juniper Networks Junos OS * 21.2 versions earlier than 21.2R3-S5; * 21.3 versions earlier than 21.3R3-S4; * 21.4 versions earlier than 21.4R3-S4; * 22.1 versions earlier than 22.1R3-S2; * 22.2 versions earlier than 22.2R3-S2; * 22.3 versions earlier than 22.3R2-S1, 22.3R3; * 22.4 versions earlier than 22.4R1-S2, 22.4R2. This issue does not affect Junos OS versions earlier than 20.4R3-S7.

Affected products

Juniper Junos OS: 21.2, 21.2-r1, 21.2-r1-s1, 21.2-r1-s2, 21.2-r2, 21.2-r2-s1 (+54)

References

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