CVE-2023-22416: Junos OS: MX Series and SRX Series: The flow processing daemon (flowd) will crash if SIP ALG is enabled and a malformed SIP packet is received

Severity: high (CVSS 7.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.7% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2023-01-13 · updated 2026-06-17
Weakness: CWE-120

Description

A Buffer Overflow vulnerability in SIP ALG of Juniper Networks Junos OS allows a network-based, unauthenticated attacker to cause a Denial of Service (DoS). On all MX Series and SRX Series platform with SIP ALG enabled, when a malformed SIP packet is received, the flow processing daemon (flowd) will crash and restart. This issue affects: Juniper Networks Junos OS on MX Series and SRX Series 20.4 versions prior to 20.4R3-S5; 21.1 versions prior to 21.1R3-S4; 21.2 versions prior to 21.2R3-S2; 21.3 versions prior to 21.3R3-S1; 21.4 versions prior to 21.4R3; 22.1 versions prior to 22.1R1-S2, 22.1R2; 22.2 versions prior to 22.2R1-S1, 22.2R2. This issue does not affect Juniper Networks Junos OS versions prior to 20.4R1 on SRX Series.

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 (+42) — fixed in 20.4

How to fix

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

References

Get alerted when CVE-2023-22416 or the next vulnerability affects your stack