CVE-2024-21594: Junos OS: SRX 5000 Series: Repeated execution of a specific CLI command causes a flowd crash

Severity: medium (CVSS 5.5 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: 2024-01-12 · updated 2026-06-17
Weakness: CWE-122

Description

A Heap-based Buffer Overflow vulnerability in the Network Services Daemon (NSD) of Juniper Networks Junos OS allows authenticated, low privileged, local attacker to cause a Denial of Service (DoS). On an SRX 5000 Series device, when executing a specific command repeatedly, memory is corrupted, which leads to a Flow Processing Daemon (flowd) crash. The NSD process has to be restarted to restore services. If this issue occurs, it can be checked with the following command: user@host> request security policies check The following log message can also be observed: Error: policies are out of sync for PFE node<number>.fpc<number>.pic<number>. This issue affects: Juniper Networks Junos OS on SRX 5000 Series * All versions earlier than 20.4R3-S6; * 21.1 versions earlier than 21.1R3-S5; * 21.2 versions earlier than 21.2R3-S4; * 21.3 versions earlier than 21.3R3-S3; * 21.4 versions earlier than 21.4R3-S3; * 22.1 versions earlier than 22.1R3-S1; * 22.2 versions earlier than 22.2R3; * 22.3 versions earlier than 22.3R2.

Affected products

Juniper Junos OS: before 20.4; 20.4, 20.4-r1, 20.4-r1-s1, 20.4-r2, 20.4-r2-s1, 20.4-r2-s2 (+67) — fixed in 20.4

How to fix

Upgrade to a fixed version: Juniper Junos OS 20.4. Check the vendor advisory for mitigations.

References

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