{"cve":"CVE-2024-21616","nvd":{"published":"2024-01-12T01:15:50.027","modified":"2026-06-17T07:09:50.927","status":"Modified","description":"An Improper Validation of Syntactic Correctness of Input vulnerability in Packet Forwarding Engine (PFE) of Juniper Networks Junos OS allows an unauthenticated, network-based attacker to cause Denial of Service (DoS).\n\nOn all Junos OS MX Series and SRX Series platforms, when SIP ALG is enabled, and a specific SIP packet is received and processed, NAT IP allocation fails for genuine traffic, which causes Denial of Service (DoS). Continuous receipt of this specific SIP ALG packet will cause a sustained DoS condition.\n\nNAT IP usage can be monitored by running the following command.\n\nuser@srx> show security nat resource-usage source-pool <source_pool_name>\n\n\nPool name: source_pool_name\n..\nAddress Factor-index Port-range Used Avail Total Usage\nX.X.X.X\n0 Single Ports 50258 52342 62464 96% <<<<<\n- Alg Ports 0 2048 2048 0%\nThis issue affects:\n\nJuniper Networks Junos OS on MX Series and SRX Series\n\n\n\n  *  All versions earlier than 21.2R3-S6;\n  *  21.3 versions earlier than 21.3R3-S5;\n  *  21.4 versions earlier than 21.4R3-S5;\n  *  22.1 versions earlier than 22.1R3-S4;\n  *  22.2 versions earlier than 22.2R3-S3;\n  *  22.3 versions earlier than 22.3R3-S1;\n  *  22.4 versions earlier than 22.4R2-S2, 22.4R3;\n  *  23.2 versions earlier than 23.2R1-S1, 23.2R2.","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","score":7.5},"cwes":["CWE-1286"],"references":["https://supportportal.juniper.net/JSA75757","https://www.first.org/cvss/calculator/4.0#CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N","https://supportportal.juniper.net/JSA75757","https://www.first.org/cvss/calculator/4.0#CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N"],"products":["juniper:junos"],"source":"nvd","synced_at":"2026-10-19T21:43:38.875533635+00:00"},"epss":{"cve":"CVE-2024-21616","score":0.00531,"percentile":0.44902,"date":"2026-10-31"},"kev":null,"osv":[],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}