{"dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": {"cveId": "CVE-2026-33774", "assignerOrgId": "8cbe9d5a-a066-4c94-8978-4b15efeae968", "state": "PUBLISHED", "assignerShortName": "juniper", "dateReserved": "2026-03-23T19:46:13.668Z", "datePublished": "2026-04-09T21:34:21.126Z", "dateUpdated": "2026-04-09T21:34:21.126Z"}, "containers": {"cna": {"affected": [{"defaultStatus": "unaffected", "platforms": ["MX Series"], "product": "Junos OS", "vendor": "Juniper Networks", "versions": [{"lessThan": "23.2R2-S6", "status": "affected", "version": "0", "versionType": "semver"}, {"lessThan": "23.4R2-S7", "status": "affected", "version": "23.4", "versionType": "semver"}, {"lessThan": "24.2R2", "status": "affected", "version": "24.2", "versionType": "semver"}, {"lessThan": "24.4R2", "status": "affected", "version": "24.4", "versionType": "semver"}]}], "datePublic": "2026-04-08T16:00:00.000Z", "descriptions": [{"lang": "en", "supportingMedia": [{"base64": false, "type": "text/html", "value": "An Improper Check for Unusual or Exceptional Conditions vulnerability in the packet forwarding engine (pfe) of Juniper Networks Junos OS on MX Series allows an unauthenticated, network-based attacker to bypass the configured firewall filter and access the control-plane of the device.<br><br><span style=\"background-color: rgb(255, 255, 255);\">On MX platforms with \n\n<span style=\"background-color: rgb(255, 255, 255);\">MPC10, MPC11, LC4800 or LC9600</span>\n\nline cards, and MX304, firewall filters applied on a loopback interface lo0.n (where n is a non-0 number) don't get executed when lo0.n is in the global VRF / default routing-instance.<br><br> An affected configuration would be:<br></span><tt><span style=\"background-color: rgb(255, 255, 255);\"><br>user@host# show configuration interfaces lo0 | display set<br>set interfaces lo0 unit 1 family inet filter input &lt;filter-name&gt;</span></tt><span style=\"background-color: rgb(255, 255, 255);\"><br><br>where a firewall filter is applied to a non-0 loopback interface, but that loopback interface is not referred to in any routing-instance (RI) configuration, which implies that it's used in the default RI.<br><br>The issue can be observed with the CLI command:<br><br></span><tt><span style=\"background-color: rgb(255, 255, 255);\">user@device&gt; show firewall counter filter &lt;filter_name&gt;</span></tt> <br><br>not showing any matches.<br><br><p>This issue affects Junos OS on MX Series:</p><ul><li>all versions before 23.2R2-S6,</li><li>23.4 versions before 23.4R2-S7,</li><li>24.2 versions before 24.2R2,</li><li>24.4 versions before 24.4R2.</li></ul><p><br></p>"}], "value": "An Improper Check for Unusual or Exceptional Conditions vulnerability in the packet forwarding engine (pfe) of Juniper Networks Junos OS on MX Series allows an unauthenticated, network-based attacker to bypass the configured firewall filter and access the control-plane of the device.\n\nOn MX platforms with \n\nMPC10, MPC11, LC4800 or LC9600\n\nline cards, and MX304, firewall filters applied on a loopback interface lo0.n (where n is a non-0 number) don't get executed when lo0.n is in the global VRF / default routing-instance.\n\n An affected configuration would be:\n\nuser@host# show configuration interfaces lo0 | display set\nset interfaces lo0 unit 1 family inet filter input <filter-name>\n\nwhere a firewall filter is applied to a non-0 loopback interface, but that loopback interface is not referred to in any routing-instance (RI) configuration, which implies that it's used in the default RI.\n\nThe issue can be observed with the CLI command:\n\nuser@device> show firewall counter filter <filter_name> \n\nnot showing any matches.\n\nThis issue affects Junos OS on MX Series:\n\n * all versions before 23.2R2-S6,\n * 23.4 versions before 23.4R2-S7,\n * 24.2 versions before 24.2R2,\n * 24.4 versions before 24.4R2."}], "exploits": [{"lang": "en", "supportingMedia": [{"base64": false, "type": "text/html", "value": "Juniper SIRT is not aware of any malicious exploitation of this vulnerability."}], "value": "Juniper SIRT is not aware of any malicious exploitation of this vulnerability."}], "metrics": [{"cvssV3_1": {"attackComplexity": "LOW", "attackVector": "NETWORK", "availabilityImpact": "NONE", "baseScore": 6.5, "baseSeverity": "MEDIUM", "confidentialityImpact": "LOW", "integrityImpact": "LOW", "privilegesRequired": "NONE", "scope": "UNCHANGED", "userInteraction": "NONE", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N", "version": "3.1"}, "format": "CVSS", "scenarios": [{"lang": "en", "value": "GENERAL"}]}, {"cvssV4_0": {"Automatable": "YES", "Recovery": "USER", "Safety": "NOT_DEFINED", "attackComplexity": "LOW", "attackRequirements": "NONE", "attackVector": "NETWORK", "baseScore": 6.9, "baseSeverity": "MEDIUM", "privilegesRequired": "NONE", "providerUrgency": "NOT_DEFINED", "subAvailabilityImpact": "NONE", "subConfidentialityImpact": "NONE", "subIntegrityImpact": "NONE", "userInteraction": "NONE", "valueDensity": "NOT_DEFINED", "vectorString": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N/AU:Y/R:U/RE:L", "version": "4.0", "vulnAvailabilityImpact": "NONE", "vulnConfidentialityImpact": "LOW", "vulnIntegrityImpact": "LOW", "vulnerabilityResponseEffort": "LOW"}, "format": "CVSS", "scenarios": [{"lang": "en", "value": "GENERAL"}]}], "problemTypes": [{"descriptions": [{"cweId": "CWE-754", "description": "CWE-754 Improper Check for Unusual or Exceptional Conditions", "lang": "en", "type": "CWE"}]}], "providerMetadata": {"orgId": "8cbe9d5a-a066-4c94-8978-4b15efeae968", "shortName": "juniper", "dateUpdated": "2026-04-09T21:34:21.126Z"}, "references": [{"tags": ["vendor-advisory"], "url": "https://kb.juniper.net/JSA107865"}], "solutions": [{"lang": "en", "supportingMedia": [{"base64": false, "type": "text/html", "value": "The following software releases have been updated to resolve this specific issue: 23.2R2-S6, 23.4R2-S7, 24.2R2, 24.4R2, 25.2R1, and all subsequent releases."}], "value": "The following software releases have been updated to resolve this specific issue: 23.2R2-S6, 23.4R2-S7, 24.2R2, 24.4R2, 25.2R1, and all subsequent releases."}], "source": {"advisory": "JSA107865", "defect": ["1855648"], "discovery": "USER"}, "title": "Junos OS: MX Series: Firewall filters on lo0.<non-0> in the default routing instance are not in effect", "workarounds": [{"lang": "en", "supportingMedia": [{"base64": false, "type": "text/html", "value": "<span style=\"background-color: rgb(255, 255, 255);\">Renaming the lo0 logical unit used in the default routing instance from non-0 to 0 resolves this issue.</span><br>"}], "value": "Renaming the lo0 logical unit used in the default routing instance from non-0 to 0 resolves this issue."}], "x_generator": {"engine": "Vulnogram 0.1.0-dev"}}}}

{}

{"cveTags": [], "descriptions": [{"lang": "en", "value": "An Improper Check for Unusual or Exceptional Conditions vulnerability in the packet forwarding engine (pfe) of Juniper Networks Junos OS on MX Series allows an unauthenticated, network-based attacker to bypass the configured firewall filter and access the control-plane of the device.\n\nOn MX platforms with \n\nMPC10, MPC11, LC4800 or LC9600\n\nline cards, and MX304, firewall filters applied on a loopback interface lo0.n (where n is a non-0 number) don't get executed when lo0.n is in the global VRF / default routing-instance.\n\n An affected configuration would be:\n\nuser@host# show configuration interfaces lo0 | display set\nset interfaces lo0 unit 1 family inet filter input <filter-name>\n\nwhere a firewall filter is applied to a non-0 loopback interface, but that loopback interface is not referred to in any routing-instance (RI) configuration, which implies that it's used in the default RI.\n\nThe issue can be observed with the CLI command:\n\nuser@device> show firewall counter filter <filter_name> \n\nnot showing any matches.\n\nThis issue affects Junos OS on MX Series:\n\n * all versions before 23.2R2-S6,\n * 23.4 versions before 23.4R2-S7,\n * 24.2 versions before 24.2R2,\n * 24.4 versions before 24.4R2."}], "id": "CVE-2026-33774", "lastModified": "2026-04-09T22:16:25.803", "metrics": {"cvssMetricV31": [{"cvssData": {"attackComplexity": "LOW", "attackVector": "NETWORK", "availabilityImpact": "NONE", "baseScore": 6.5, "baseSeverity": "MEDIUM", "confidentialityImpact": "LOW", "integrityImpact": "LOW", "privilegesRequired": "NONE", "scope": "UNCHANGED", "userInteraction": "NONE", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N", "version": "3.1"}, "exploitabilityScore": 3.9, "impactScore": 2.5, "source": "sirt@juniper.net", "type": "Primary"}], "cvssMetricV40": [{"cvssData": {"Automatable": "YES", "Recovery": "USER", "Safety": "NOT_DEFINED", "attackComplexity": "LOW", "attackRequirements": "NONE", "attackVector": "NETWORK", "availabilityRequirement": "NOT_DEFINED", "baseScore": 6.9, "baseSeverity": "MEDIUM", "confidentialityRequirement": "NOT_DEFINED", "exploitMaturity": "NOT_DEFINED", "integrityRequirement": "NOT_DEFINED", "modifiedAttackComplexity": "NOT_DEFINED", "modifiedAttackRequirements": "NOT_DEFINED", "modifiedAttackVector": "NOT_DEFINED", "modifiedPrivilegesRequired": "NOT_DEFINED", "modifiedSubAvailabilityImpact": "NOT_DEFINED", "modifiedSubConfidentialityImpact": "NOT_DEFINED", "modifiedSubIntegrityImpact": "NOT_DEFINED", "modifiedUserInteraction": "NOT_DEFINED", "modifiedVulnAvailabilityImpact": "NOT_DEFINED", "modifiedVulnConfidentialityImpact": "NOT_DEFINED", "modifiedVulnIntegrityImpact": "NOT_DEFINED", "privilegesRequired": "NONE", "providerUrgency": "NOT_DEFINED", "subAvailabilityImpact": "NONE", "subConfidentialityImpact": "NONE", "subIntegrityImpact": "NONE", "userInteraction": "NONE", "valueDensity": "NOT_DEFINED", "vectorString": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:Y/R:U/V:X/RE:L/U:X", "version": "4.0", "vulnAvailabilityImpact": "NONE", "vulnConfidentialityImpact": "LOW", "vulnIntegrityImpact": "LOW", "vulnerabilityResponseEffort": "LOW"}, "source": "sirt@juniper.net", "type": "Secondary"}]}, "published": "2026-04-09T22:16:25.803", "references": [{"source": "sirt@juniper.net", "url": "https://kb.juniper.net/JSA107865"}], "sourceIdentifier": "sirt@juniper.net", "vulnStatus": "Received", "weaknesses": [{"description": [{"lang": "en", "value": "CWE-754"}], "source": "sirt@juniper.net", "type": "Primary"}]}

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