{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2026-21920", "assignerOrgId": "8cbe9d5a-a066-4c94-8978-4b15efeae968", "state": "PUBLISHED", "assignerShortName": "juniper", "dateReserved": "2026-01-05T17:32:48.712Z", "datePublished": "2026-01-15T20:28:10.526Z", "dateUpdated": "2026-01-15T20:59:21.070Z" }, "containers": { "cna": { "affected": [ { "defaultStatus": "unaffected", "platforms": [ "SRX Series" ], "product": "Junos OS", "vendor": "Juniper Networks", "versions": [ { "lessThan": "23.4R2-S5", "status": "affected", "version": "23.4", "versionType": "semver" }, { "lessThan": "24.2R2-S1", "status": "affected", "version": "24.2", "versionType": "semver" }, { "lessThan": "24.4R2", "status": "affected", "version": "24.4", "versionType": "semver" }, { "lessThan": "23.4R1", "status": "unaffected", "version": "0", "versionType": "semver" } ] } ], "configurations": [ { "lang": "en", "supportingMedia": [ { "base64": false, "type": "text/html", "value": "A device is exposed to this issue when one of the following features are used / configurations are present:

- GeoIP:

[ security dynamic-address address-name <name> profile category GeoIP ... ]


- DNS security:

[ services security-metadata-streaming policy <name> dns detections ... ]

or

[ services security-intelligence profile <profile-name> category DNS ]
[ services security-intelligence profile policy <policy-name> DNS <profile-name> ]

\n\n" } ], "value": "A device is exposed to this issue when one of the following features are used / configurations are present:\n\n- GeoIP:\n\n[ security dynamic-address address-name profile category GeoIP ... ]\n\n\n- DNS security:\n\n[ services security-metadata-streaming policy dns detections ... ]\n\nor\n\n[ services security-intelligence profile category DNS ]\n[ services security-intelligence profile policy DNS ]" } ], "datePublic": "2026-01-14T17:00:00.000Z", "descriptions": [ { "lang": "en", "supportingMedia": [ { "base64": false, "type": "text/html", "value": "An Unchecked Return Value vulnerability in the DNS module of Juniper Networks Junos OS on SRX Series allows an unauthenticated, network-based attacker to cause a Denial-of-Service (DoS).
\n\n

If an SRX Series device configured for DNS processing, receives a specifically formatted DNS request flowd will crash and restart, which causes a service interruption until the process has recovered.

This issue affects Junos OS on SRX Series:

  • 23.4 versions before 23.4R2-S5,
  • 24.2 versions before 24.2R2-S1,
  • 24.4 versions before 24.4R2.

\n\n

This issue does not affect Junos OS versions before 23.4R1.

" } ], "value": "An Unchecked Return Value vulnerability in the DNS module of Juniper Networks Junos OS on SRX Series allows an unauthenticated, network-based attacker to cause a Denial-of-Service (DoS).\n\n\n\n\nIf an SRX Series device configured for DNS processing, receives a specifically formatted DNS request flowd will crash and restart, which causes a service interruption until the process has recovered.\n\nThis issue affects Junos OS on SRX Series:\n\n\n\n * 23.4 versions before 23.4R2-S5,\n * 24.2 versions before 24.2R2-S1,\n * 24.4 versions before 24.4R2.\n\n\n\n\n\n\nThis issue does not affect Junos OS versions before 23.4R1." } ], "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": "HIGH", "baseScore": 7.5, "baseSeverity": "HIGH", "confidentialityImpact": "NONE", "integrityImpact": "NONE", "privilegesRequired": "NONE", "scope": "UNCHANGED", "userInteraction": "NONE", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H", "version": "3.1" }, "format": "CVSS", "scenarios": [ { "lang": "en", "value": "GENERAL" } ] }, { "cvssV4_0": { "Automatable": "YES", "Recovery": "AUTOMATIC", "Safety": "NOT_DEFINED", "attackComplexity": "LOW", "attackRequirements": "NONE", "attackVector": "NETWORK", "baseScore": 8.7, "baseSeverity": "HIGH", "privilegesRequired": "NONE", "providerUrgency": "NOT_DEFINED", "subAvailabilityImpact": "LOW", "subConfidentialityImpact": "NONE", "subIntegrityImpact": "NONE", "userInteraction": "NONE", "valueDensity": "NOT_DEFINED", "vectorString": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:L/AU:Y/R:A/RE:M", "version": "4.0", "vulnAvailabilityImpact": "HIGH", "vulnConfidentialityImpact": "NONE", "vulnIntegrityImpact": "NONE", "vulnerabilityResponseEffort": "MODERATE" }, "format": "CVSS", "scenarios": [ { "lang": "en", "value": "GENERAL" } ] } ], "problemTypes": [ { "descriptions": [ { "cweId": "CWE-252", "description": "CWE-252 Unchecked Return Value", "lang": "en", "type": "CWE" } ] } ], "providerMetadata": { "orgId": "8cbe9d5a-a066-4c94-8978-4b15efeae968", "shortName": "juniper", "dateUpdated": "2026-01-15T20:28:10.526Z" }, "references": [ { "tags": [ "vendor-advisory" ], "url": "https://supportportal.juniper.net/JSA106020" }, { "tags": [ "vendor-advisory" ], "url": "https://kb.juniper.net/JSA106020" } ], "solutions": [ { "lang": "en", "supportingMedia": [ { "base64": false, "type": "text/html", "value": "The following software releases have been updated to resolve this specific issue: 23.4R2-S5, 24.2R2-S1, 24.4R2, 24.4R2-S1, 25.2R1, and all subsequent releases." } ], "value": "The following software releases have been updated to resolve this specific issue: 23.4R2-S5, 24.2R2-S1, 24.4R2, 24.4R2-S1, 25.2R1, and all subsequent releases." } ], "source": { "advisory": "JSA106020", "defect": [ "1851909" ], "discovery": "USER" }, "title": "Junos OS: SRX Series: If a specific request is processed by the DNS subsystem flowd will crash", "workarounds": [ { "lang": "en", "supportingMedia": [ { "base64": false, "type": "text/html", "value": "There are no known workarounds for this issue." } ], "value": "There are no known workarounds for this issue." } ], "x_generator": { "engine": "Vulnogram 0.1.0-dev" } }, "adp": [ { "metrics": [ { "other": { "type": "ssvc", "content": { "timestamp": "2026-01-15T20:58:50.543674Z", "id": "CVE-2026-21920", "options": [ { "Exploitation": "none" }, { "Automatable": "yes" }, { "Technical Impact": "partial" } ], "role": "CISA Coordinator", "version": "2.0.3" } } } ], "title": "CISA ADP Vulnrichment", "providerMetadata": { "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "shortName": "CISA-ADP", "dateUpdated": "2026-01-15T20:59:21.070Z" } } ] } }