{"id":"CVE-2026-57031","title":"An Improper Check for Unusual or Exceptional Conditions vulnerability in the packet forwarding engine (PFE) of Juniper Networks Junos OS on MX Series allows adjacent subscribers to bypass configured firewall filters.\n\nOn MX Series device…","summary":"An Improper Check for Unusual or Exceptional Conditions vulnerability in the packet forwarding engine (PFE) of Juniper Networks Junos OS on MX Series allows adjacent subscribers to bypass configured firewall filters.\n\nOn MX Series device…","severity":"medium","cvss":4.7,"cvssVector":"CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:N","cwe":["CWE-754"],"vendor":"juniper","product":"junos","affected":["junos = 23.2","junos = 23.4","junos = 24.2","junos = 24.4","junos = 25.2"],"published":"2026-07-09","updated":"2026-08-25","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-57031","references":[{"url":"https://supportportal.juniper.net/JSA110091","label":"sirt@juniper.net"}],"tags":["nvd"],"epss":0.00223,"epssPercentile":0.13231,"ingestedAt":"2026-08-26T14:45:07.946Z","slug":"CVE-2026-57031","body":"## Overview\n\nAn Improper Check for Unusual or Exceptional Conditions vulnerability in the packet forwarding engine (PFE) of Juniper Networks Junos OS on MX Series allows adjacent subscribers to bypass configured firewall filters.\n\nOn MX Series devices with MPC10/11, LC4800/9600, and MX304 with subscribers configured on static interfaces, ingress firewall filters are not enforced, so that neither protocol level nor upstream bandwidth limitation are in effect. \n\n\nThis issue affects Junos OS on MX with MPC10/11, LC4800/9600/4802, and MX304:\n\n\n  *  23.2 versions from 23.2R2-S1 before 23.2R2-S7,\n  *  23.4 versions from 23.4R2 before 23.4R2-S7,\n  *  24.2 versions before 24.2R2-S3,\n  *  24.4 versions before 24.4R2-S2,\n  *  25.2 versions before 25.2R2.\n\n## Affected\n\n- `junos = 23.2`\n- `junos = 23.4`\n- `junos = 24.2`\n- `junos = 24.4`\n- `junos = 25.2`\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.","depth":"sunlit","depthScore":26,"depthScoreParts":{"impact":25.9,"likelihood":0,"exploitation":0,"ransomware":0},"changes":[]}