CVE-2023-22408: An Improper Validation of Array Index vulnerability in the SIP ALG of Juniper Networks Junos OS on SRX 5000 Series allows a network-based, unauthentic...

Description

An Improper Validation of Array Index vulnerability in the SIP ALG of Juniper Networks Junos OS on SRX 5000 Series allows a network-based, unauthenticated attacker to cause a Denial of Service (DoS). When an attacker sends an SIP packets with a malformed SDP field then the SIP ALG can not process it which will lead to an FPC crash and restart. Continued receipt of these specific packets will lead to a sustained Denial of Service. This issue can only occur when both below mentioned conditions are fulfilled: 1. Call distribution needs to be enabled: [security alg sip enable-call-distribution] 2. The SIP ALG needs to be enabled, either implicitly / by default or by way of configuration. To confirm whether SIP ALG is enabled on SRX, and MX with SPC3 use the following command: user@host> show security alg status | match sip SIP : Enabled This issue affects Juniper Networks Junos OS on SRX 5000 Series: 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-S2; 22.1 versions prior to 22.1R2-S2, 22.1R3; 22.2 versions prior to 22.2R3; 22.3 versions prior to 22.3R1-S1, 22.3R2. This issue does not affect Juniper Networks Junos OS versions prior to 20.4R1.

Metrics

CVSS 3.1

7.5/10

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

EPSS Probability

0.63%

45.4th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

Affected Software

Vendor	Product	Versions	Update
Juniper	Junos	20.4	—
Juniper	Junos	21.1	—
Juniper	Junos	21.2	—
Juniper	Junos	21.3	—
Juniper	Junos	21.4	—
Juniper	Junos	22.1	R1
Juniper	Junos	22.2	R1
Juniper	Junos	22.3	R1

References

https://kb.juniper.net/JSA70204Vendor Advisory
https://kb.juniper.net/JSA70204Vendor Advisory

Timeline

Published: Jan 13, 2023
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2023-22408?

An Improper Validation of Array Index vulnerability in the SIP ALG of Juniper Networks Junos OS on SRX 5000 Series allows a network-based, unauthenticated attacker to cause a Denial of Service (DoS). When an attacker sends an SIP packets with a malformed SDP field then the SIP ALG can not process it which will lead to an FPC crash and restart. Continued receipt of these specific packets will lead to a sustained Denial of Service. This issue can only occur when both below mentioned conditions are fulfilled: 1. Call distribution needs to be enabled: [security alg sip enable-call-distribution] 2. The SIP ALG needs to be enabled, either implicitly / by default or by way of configuration. To confirm whether SIP ALG is enabled on SRX, and MX with SPC3 use the following command: user@host> show security alg status | match sip SIP : Enabled This issue affects Juniper Networks Junos OS on SRX 5000 Series: 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-S2; 22.1 versions prior to 22.1R2-S2, 22.1R3; 22.2 versions prior to 22.2R3; 22.3 versions prior to 22.3R1-S1, 22.3R2. This issue does not affect Juniper Networks Junos OS versions prior to 20.4R1.

How severe is CVE-2023-22408?

CVE-2023-22408 has a CVSS score of 7.5/10 (HIGH severity). The EPSS model estimates a 0.63% probability of exploitation in the next 30 days.

How do I fix CVE-2023-22408?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.