CVE-2023-22415: Junos OS: MX Series and SRX Series: The flow processing daemon (flowd) will crash when specific H.323 packets are received

Severity: high (CVSS 7.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.8% probability of exploitation in the next 30 days
Public exploit or detection template: yes
Published: 2023-01-13 · updated 2026-06-17
Weakness: CWE-787

Description

An Out-of-Bounds Write vulnerability in the H.323 ALG of Juniper Networks Junos OS allows an unauthenticated, network-based attacker to cause Denial of Service (DoS). On all MX Series and SRX Series platform, when H.323 ALG is enabled and specific H.323 packets are received simultaneously, a flow processing daemon (flowd) crash will occur. Continued receipt of these specific packets will cause a sustained Denial of Service (DoS) condition. This issue affects: Juniper Networks Junos OS on MX Series and SRX Series All versions prior to 19.4R3-S10; 20.2 versions prior to 20.2R3-S6; 20.3 versions prior to 20.3R3-S6; 20.4 versions prior to 20.4R3-S5; 21.1 versions prior to 21.1R3-S4; 21.2 versions prior to 21.2R3-S3; 21.3 versions prior to 21.3R3-S3; 21.4 versions prior to 21.4R3; 22.1 versions prior to 22.1R2-S1, 22.1R3; 22.2 versions prior to 22.2R1-S2, 22.2R2.

Affected products

Juniper Junos OS: before 19.4; 19.4, 19.4-r1, 19.4-r1-s1, 19.4-r1-s2, 19.4-r1-s3, 19.4-r1-s4 (+98) — fixed in 19.4

How to fix

Upgrade to a fixed version: Juniper Junos OS 19.4. Check the vendor advisory for mitigations.

References

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