{"dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": {"cveId": "CVE-2026-21905", "assignerOrgId": "8cbe9d5a-a066-4c94-8978-4b15efeae968", "state": "PUBLISHED", "assignerShortName": "juniper", "dateReserved": "2026-01-05T17:32:48.710Z", "datePublished": "2026-01-15T20:19:22.158Z", "dateUpdated": "2026-01-15T20:19:22.158Z"}, "containers": {"cna": {"affected": [{"defaultStatus": "unaffected", "platforms": ["SRX Series", "MX Series with MX-SPC3", "MX Series with MS-MPC"], "product": "Junos OS", "vendor": "Juniper Networks", "versions": [{"lessThan": "21.2R3-S10", "status": "affected", "version": "0", "versionType": "semver"}, {"lessThan": "21.4R3-S12", "status": "affected", "version": "21.4", "versionType": "semver"}, {"lessThan": "22.4R3-S8", "status": "affected", "version": "22.4", "versionType": "semver"}, {"lessThan": "23.2R2-S5", "status": "affected", "version": "23.2", "versionType": "semver"}, {"lessThan": "23.4R2-S6", "status": "affected", "version": "23.4", "versionType": "semver"}, {"lessThan": "24.2R2-S3", "status": "affected", "version": "24.2", "versionType": "semver"}, {"lessThan": "24.4R2-S1", "status": "affected", "version": "24.4", "versionType": "semver"}, {"lessThan": "25.2R1-S1, 25.2R2", "status": "affected", "version": "25.2", "versionType": "semver"}]}], "configurations": [{"lang": "en", "supportingMedia": [{"base64": false, "type": "text/html", "value": "The SIP ALG must be enabled to be vulnerable to this issue. The SIP ALG is enabled by default on MX-SPC3 and some SRX Series platforms. For other platforms, the following configuration is required:<br><br>\n\n<tt><span style=\"background-color: rgb(255, 255, 255);\">[security alg sip enable]</span></tt><br>\n<br>On SRX Series and MX Series with MX-SPC3, the SIP ALG status can be confirmed via the 'show security alg status' command:<br>\n<br>\n<tt>user@junos&gt; show security alg status</tt><br>\n<tt>ALG Status:</tt><br>\n...<br>\n<tt>&nbsp; SIP &nbsp; &nbsp; : Enabled</tt><br>"}], "value": "The SIP ALG must be enabled to be vulnerable to this issue. The SIP ALG is enabled by default on MX-SPC3 and some SRX Series platforms. For other platforms, the following configuration is required:\n\n\n\n[security alg sip enable]\n\n\nOn SRX Series and MX Series with MX-SPC3, the SIP ALG status can be confirmed via the 'show security alg status' command:\n\n\n\nuser@junos> show security alg status\n\nALG Status:\n\n...\n\n\u00a0 SIP \u00a0 \u00a0 : Enabled"}], "datePublic": "2026-01-14T17:00:00.000Z", "descriptions": [{"lang": "en", "supportingMedia": [{"base64": false, "type": "text/html", "value": "A Loop with Unreachable Exit Condition ('Infinite Loop') vulnerability in the SIP application layer gateway (ALG) of Juniper Networks Junos OS on SRX Series and MX Series with MX-SPC3 or MS-MPC allows an unauthenticated network-based attacker sending specific SIP messages over TCP to crash the flow management process, leading to a Denial of Service (DoS).<br><br>On SRX Series, and MX Series with MX-SPC3 or MS-MPC service cards, receipt of multiple SIP messages causes the SIP headers to be parsed incorrectly, eventually causing a continuous loop and leading to a watchdog timer expiration, crashing the flowd process on SRX Series and MX Series with MX-SPC3, or mspmand process on MX Series with MS-MPC.<br><br>This issue only occurs over TCP. SIP messages sent over UDP cannot trigger this issue.<br><br><p>This issue affects Junos OS on SRX Series and MX Series with MX-SPC3 and MS-MPC:</p><p></p><ul><li>all versions before 21.2R3-S10,&nbsp;</li><li>from 21.4 before 21.4R3-S12,&nbsp;</li><li>from 22.4 before 22.4R3-S8,&nbsp;</li><li>from 23.2 before 23.2R2-S5,&nbsp;</li><li>from 23.4 before 23.4R2-S6,&nbsp;</li><li>from 24.2 before 24.2R2-S3,&nbsp;</li><li>from 24.4 before 24.4R2-S1,&nbsp;</li><li>from 25.2 before 25.2R1-S1, 25.2R2.</li></ul><p></p>"}], "value": "A Loop with Unreachable Exit Condition ('Infinite Loop') vulnerability in the SIP application layer gateway (ALG) of Juniper Networks Junos OS on SRX Series and MX Series with MX-SPC3 or MS-MPC allows an unauthenticated network-based attacker sending specific SIP messages over TCP to crash the flow management process, leading to a Denial of Service (DoS).\n\nOn SRX Series, and MX Series with MX-SPC3 or MS-MPC service cards, receipt of multiple SIP messages causes the SIP headers to be parsed incorrectly, eventually causing a continuous loop and leading to a watchdog timer expiration, crashing the flowd process on SRX Series and MX Series with MX-SPC3, or mspmand process on MX Series with MS-MPC.\n\nThis issue only occurs over TCP. SIP messages sent over UDP cannot trigger this issue.\n\nThis issue affects Junos OS on SRX Series and MX Series with MX-SPC3 and MS-MPC:\n\n\n\n * all versions before 21.2R3-S10,\u00a0\n * from 21.4 before 21.4R3-S12,\u00a0\n * from 22.4 before 22.4R3-S8,\u00a0\n * from 23.2 before 23.2R2-S5,\u00a0\n * from 23.4 before 23.4R2-S6,\u00a0\n * from 24.2 before 24.2R2-S3,\u00a0\n * from 24.4 before 24.4R2-S1,\u00a0\n * from 25.2 before 25.2R1-S1, 25.2R2."}], "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": "AMBER", "subAvailabilityImpact": "LOW", "subConfidentialityImpact": "NONE", "subIntegrityImpact": "NONE", "userInteraction": "NONE", "valueDensity": "CONCENTRATED", "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/V:C/RE:M/U:Amber", "version": "4.0", "vulnAvailabilityImpact": "HIGH", "vulnConfidentialityImpact": "NONE", "vulnIntegrityImpact": "NONE", "vulnerabilityResponseEffort": "MODERATE"}, "format": "CVSS", "scenarios": [{"lang": "en", "value": "GENERAL"}]}], "problemTypes": [{"descriptions": [{"cweId": "CWE-835", "description": "CWE-835 Loop with Unreachable Exit Condition ('Infinite Loop')", "lang": "en", "type": "CWE"}]}], "providerMetadata": {"orgId": "8cbe9d5a-a066-4c94-8978-4b15efeae968", "shortName": "juniper", "dateUpdated": "2026-01-15T20:19:22.158Z"}, "references": [{"tags": ["vendor-advisory"], "url": "https://supportportal.juniper.net/JSA106004"}, {"tags": ["vendor-advisory"], "url": "https://kb.juniper.net/JSA106004"}], "solutions": [{"lang": "en", "supportingMedia": [{"base64": false, "type": "text/html", "value": "The following software releases have been updated to resolve this specific issue: 21.2R3-S10, 21.4R3-S12, 22.4R3-S8, 23.2R2-S5, 23.4R2-S6, 24.2R2-S3, 24.4R2-S1, 25.2R1-S1, 25.2R2, 25.4R1, and all subsequent releases."}], "value": "The following software releases have been updated to resolve this specific issue: 21.2R3-S10, 21.4R3-S12, 22.4R3-S8, 23.2R2-S5, 23.4R2-S6, 24.2R2-S3, 24.4R2-S1, 25.2R1-S1, 25.2R2, 25.4R1, and all subsequent releases."}], "source": {"advisory": "JSA106004", "defect": ["1876029"], "discovery": "USER"}, "title": "Junos OS: SRX Series, MX Series with MX-SPC3 or MS-MPC: Receipt of multiple specific SIP messages results in flow management process crash", "workarounds": [{"lang": "en", "supportingMedia": [{"base64": false, "type": "text/html", "value": "Where practical, use a firewall filter to limit SIP traffic over TCP.<br><br>Alternately, if the SIP ALG is not required, it can be explicitly disabled on SRX Series and MX Series with MX-SPC3 via:<br><br><tt># set security alg sip disable</tt><br><br>"}], "value": "Where practical, use a firewall filter to limit SIP traffic over TCP.\n\nAlternately, if the SIP ALG is not required, it can be explicitly disabled on SRX Series and MX Series with MX-SPC3 via:\n\n# set security alg sip disable"}], "x_generator": {"engine": "Vulnogram 0.1.0-dev"}}}}

{}

{"cveTags": [], "descriptions": [{"lang": "en", "value": "A Loop with Unreachable Exit Condition ('Infinite Loop') vulnerability in the SIP application layer gateway (ALG) of Juniper Networks Junos OS on SRX Series and MX Series with MX-SPC3 or MS-MPC allows an unauthenticated network-based attacker sending specific SIP messages over TCP to crash the flow management process, leading to a Denial of Service (DoS).\n\nOn SRX Series, and MX Series with MX-SPC3 or MS-MPC service cards, receipt of multiple SIP messages causes the SIP headers to be parsed incorrectly, eventually causing a continuous loop and leading to a watchdog timer expiration, crashing the flowd process on SRX Series and MX Series with MX-SPC3, or mspmand process on MX Series with MS-MPC.\n\nThis issue only occurs over TCP. SIP messages sent over UDP cannot trigger this issue.\n\nThis issue affects Junos OS on SRX Series and MX Series with MX-SPC3 and MS-MPC:\n\n\n\n * all versions before 21.2R3-S10,\u00a0\n * from 21.4 before 21.4R3-S12,\u00a0\n * from 22.4 before 22.4R3-S8,\u00a0\n * from 23.2 before 23.2R2-S5,\u00a0\n * from 23.4 before 23.4R2-S6,\u00a0\n * from 24.2 before 24.2R2-S3,\u00a0\n * from 24.4 before 24.4R2-S1,\u00a0\n * from 25.2 before 25.2R1-S1, 25.2R2."}], "id": "CVE-2026-21905", "lastModified": "2026-01-15T21:16:05.990", "metrics": {"cvssMetricV31": [{"cvssData": {"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"}, "exploitabilityScore": 3.9, "impactScore": 3.6, "source": "sirt@juniper.net", "type": "Primary"}], "cvssMetricV40": [{"cvssData": {"Automatable": "YES", "Recovery": "AUTOMATIC", "Safety": "NOT_DEFINED", "attackComplexity": "LOW", "attackRequirements": "NONE", "attackVector": "NETWORK", "availabilityRequirement": "NOT_DEFINED", "baseScore": 8.7, "baseSeverity": "HIGH", "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": "AMBER", "subAvailabilityImpact": "LOW", "subConfidentialityImpact": "NONE", "subIntegrityImpact": "NONE", "userInteraction": "NONE", "valueDensity": "CONCENTRATED", "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/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:A/V:C/RE:M/U:Amber", "version": "4.0", "vulnAvailabilityImpact": "HIGH", "vulnConfidentialityImpact": "NONE", "vulnIntegrityImpact": "NONE", "vulnerabilityResponseEffort": "MODERATE"}, "source": "sirt@juniper.net", "type": "Secondary"}]}, "published": "2026-01-15T21:16:05.990", "references": [{"source": "sirt@juniper.net", "url": "https://kb.juniper.net/JSA106004"}, {"source": "sirt@juniper.net", "url": "https://supportportal.juniper.net/JSA106004"}], "sourceIdentifier": "sirt@juniper.net", "vulnStatus": "Received", "weaknesses": [{"description": [{"lang": "en", "value": "CWE-835"}], "source": "sirt@juniper.net", "type": "Primary"}]}

{}

{}