CVE-2024-39560: Junos OS and Junos OS Evolved: Memory leak due to RSVP neighbor persistent error leading to kernel crash

Severity: medium (CVSS 6.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.2% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2024-07-10 · updated 2026-06-17
Weakness: CWE-755

Description

An Improper Handling of Exceptional Conditions vulnerability in the routing protocol daemon (rpd) of Juniper Networks Junos OS and Junos OS Evolved allows a logically adjacent downstream RSVP neighbor to cause kernel memory exhaustion, leading to a kernel crash, resulting in a Denial of Service (DoS). The kernel memory leak and eventual crash will be seen when the downstream RSVP neighbor has a persistent error which will not be corrected. System kernel memory can be monitored through the use of the 'show system kernel memory' command as shown below: user@router> show system kernel memory Real memory total/reserved: 4130268/ 133344 Kbytes kmem map free: 18014398509110220 Kbytes This issue affects: Junos OS: * All versions before 20.4R3-S9, * All versions of 21.2, * from 21.4 before 21.4R3-S5, * from 22.1 before 22.1R3-S5, * from 22.2 before 22.2R3-S3, * from 22.3 before 22.3R3-S2, * from 22.4 before 22.4R3, * from 23.2 before 23.2R2; Junos OS Evolved: * All versions before 21.4R3-S5-EVO, * from 22.1-EVO before 22.1R3-S5-EVO, * from 22.2-EVO before 22.2R3-S3-EVO, * from 22.3-EVO before 22.3R3-S2-EVO, * from 22.4-EVO before 22.4R3-EVO, * from 23.2-EVO before 23.2R2-EVO.

Affected products

Juniper Junos OS: before 20.4; from 21.2 before 21.3; 20.4, 20.4-r1, 20.4-r1-s1, 20.4-r2, 20.4-r2-s1, 20.4-r2-s2 (+63) — fixed in 20.4, 21.3
Juniper Networks Junos OS Evolved: before 21.4; 21.4, 21.4-r1, 21.4-r1-s1, 21.4-r1-s2, 21.4-r2, 21.4-r2-s1 (+47) — fixed in 21.4

How to fix

Upgrade to a fixed version: Juniper Junos OS 20.4, 21.3; Juniper Networks Junos OS Evolved 21.4. Check the vendor advisory for mitigations.

References

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