Junos OS: SRX Series, MX Series with SPC3: When an inconsistent NAT configuration exists and a specific CLI command is issued the SPC will reboot

Description

An Unchecked Input for Loop Condition vulnerability in a NAT library of Juniper Networks Junos OS allows a local authenticated attacker with low privileges to cause a Denial of Service (DoS). When an inconsistent "deterministic NAT" configuration is present on an SRX, or MX with SPC3 and then a specific CLI command is issued the SPC will crash and restart. Repeated execution of this command will lead to a sustained DoS. Such a configuration is characterized by the total number of port blocks being greater than the total number of hosts. An example for such configuration is: [ services nat source pool TEST-POOL address x.x.x.0/32 to x.x.x.15/32 ] [ services nat source pool TEST-POOL port deterministic block-size 1008 ] [ services nat source pool TEST-POOL port deterministic host address y.y.y.0/24] [ services nat source pool TEST-POOL port deterministic include-boundary-addresses] where according to the following calculation: 65536-1024=64512 (number of usable ports per IP address, implicit) 64512/1008=64 (number of port blocks per Nat IP) x.x.x.0/32 to x.x.x.15/32 = 16 (NAT IP addresses available in NAT pool) total port blocks in NAT Pool = 64 blocks per IP * 16 IPs = 1024 Port blocks host address y.y.y.0/24 = 256 hosts (with include-boundary-addresses) If the port block size is configured to be 4032, then the total port blocks are (64512/4032) * 16 = 256 which is equivalent to the total host addresses of 256, and the issue will not be seen. This issue affects Juniper Networks Junos OS on SRX Series, and MX Series with SPC3: All versions prior to 19.4R3-S10; 20.1 version 20.1R1 and later versions; 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-S1; 22.1 versions prior to 22.1R2-S2, 22.1R3; 22.2 versions prior to 22.2R2.

Timeline

Scores

EPSS (exploitation in 30 days)

0.18% · top 92% of all CVEs (7 Nov 2026)

CISA SSVC

Exploitation: none · Automatable: no · Technical impact: partial

The list uses the assigner's score when there is one, then CISA's, then NVD's: Medium 5.5.

Weakness

• 606 Unchecked Input for Loop Condition
• Denial of Service (DoS)
• CWE-1284 (opens in a new tab)All about CWE-1284 and its CVEs

Affected products

• Juniper Networks · Junos OS

  • affected unspecified – < 19.4R3-S10
  • affected 20.1R1 – < 20.1*
  • affected 20.2 – < 20.2R3-S6
  • affected 20.3 – < 20.3R3-S6
  • affected 20.4 – < 20.4R3-S5
  • affected 21.1 – < 21.1R3-S4
  • affected 21.2 – < 21.2R3-S3
  • affected 21.3 – < 21.3R3-S3
  • affected 21.4 – < 21.4R3-S1
  • affected 22.1 – < 22.1R2-S2, 22.1R3
  • affected 22.2 – < 22.2R2

What to do

Solution: The following software releases have been updated to resolve this specific issue: 19.4R3-S10, 20.2R3-S6, 20.3R3-S6, 20.4R3-S5, 21.1R3-S4, 21.2R3-S3, 21.3R3-S3, 21.4R3-S1, 22.1R2-S2, 22.1R3, 22.2R2, 22.3R1, and all subsequent releases.

Workaround: Please ensure the deterministic NAT configuration is consistent as shown in the description of the problem section.

Exploitation: Juniper SIRT is not aware of any malicious exploitation of this vulnerability.

References (1)

• https://kb.juniper.net/JSA70205 (opens in a new tab)x_transferred

Sources

The same CVE in the primary databases and aggregators, to check against.

• CVE.org record (opens in a new tab)
• CVE List JSON (GitHub) (opens in a new tab)
• NVD (opens in a new tab)
• FIRST EPSS (opens in a new tab)
• OSV.dev (opens in a new tab)
• GitHub Advisories (opens in a new tab)
• CIRCL Vulnerability-Lookup (opens in a new tab)

Badge for a README or a ticket

[![CVE-2023-22409](https://trackcve.app/badge/CVE-2023-22409.svg)](https://trackcve.app/cve/CVE-2023-22409)

Record last updated 7 Apr 2025, 15:33 UTC.