{"cve":"CVE-2024-21600","nvd":{"published":"2024-01-12T01:15:47.857","modified":"2026-06-17T07:09:48.250","status":"Modified","description":"An Improper Neutralization of Equivalent Special Elements vulnerability in the Packet Forwarding Engine (PFE) of Juniper Networks Junos OS on PTX Series allows a unauthenticated, adjacent attacker to cause a Denial of Service (DoS).\n\nWhen MPLS packets are meant to be sent to a flexible tunnel interface (FTI) and if the FTI tunnel is down, these will hit the reject NH, due to which the packets get sent to the CPU and cause a host path wedge condition. This will cause the FPC to hang and requires a manual restart to recover.\n\nPlease note that this issue specifically affects PTX1000, PTX3000, PTX5000 with FPC3, PTX10002-60C, and PTX10008/16 with LC110x. Other PTX Series devices and Line Cards (LC) are not affected.\n\nThe following log message can be seen when the issue occurs:\n\nCmerror Op Set: Host Loopback: HOST LOOPBACK WEDGE DETECTED IN PATH ID <id> (URI: /fpc/<fpc>/pfe/<pfe>/cm/<cm>/Host_Loopback/<cm>/HOST_LOOPBACK_MAKE_CMERROR_ID[<id>])\nThis issue affects Juniper Networks Junos OS:\n\n\n\n  *  All versions earlier than 20.4R3-S8;\n  *  21.1 versions earlier than 21.1R3-S4;\n  *  21.2 versions earlier than 21.2R3-S6;\n  *  21.3 versions earlier than 21.3R3-S3;\n  *  21.4 versions earlier than 21.4R3-S5;\n  *  22.1 versions earlier than 22.1R2-S2, 22.1R3;\n  *  22.2 versions earlier than 22.2R2-S1, 22.2R3.","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","score":6.5},"cwes":["CWE-76"],"references":["https://supportportal.juniper.net/JSA75741","https://www.first.org/cvss/calculator/4.0#CVSS:4.0/AV:A/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:L","https://supportportal.juniper.net/JSA75741","https://www.first.org/cvss/calculator/4.0#CVSS:4.0/AV:A/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:L"],"products":["juniper:junos"],"source":"nvd","synced_at":"2026-10-19T21:43:38.875533635+00:00"},"epss":{"cve":"CVE-2024-21600","score":0.00324,"percentile":0.25514,"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."]}