CVE-2023-22409

CVE-2023-22409 is a medium-severity vulnerability in Juniper Junos with a CVSS 3.x base score of 5.5. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-1284.

Key facts

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.

Frequently asked questions

What is CVE-2023-22409?
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.
How severe is CVE-2023-22409?
CVE-2023-22409 has a CVSS 3.x base score of 5.5, rated medium severity. It is exploitable over local access with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.
Is CVE-2023-22409 being actively exploited?
It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (7th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2023-22409?
CVE-2023-22409 primarily affects Juniper Junos. In total, 122 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2023-22409?
Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2023-22409 published?
CVE-2023-22409 was published on 2023-01-13 and last updated on 2026-06-17.

References

Affected products (122)

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