CVE-2026-21911

{"id": "CVE-2026-21911", "cveTags": [], "metrics": {"ssvcV203": [{"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "ssvcData": {"id": "CVE-2026-21911", "role": "CISA Coordinator", "options": [{"exploitation": "none"}, {"automatable": "no"}, {"technicalImpact": "partial"}], "version": "2.0.3", "timestamp": "2026-01-15T20:51:26.965443Z"}}], "cvssMetricV31": [{"type": "Secondary", "source": "sirt@juniper.net", "cvssData": {"scope": "UNCHANGED", "version": "3.1", "baseScore": 6.5, "attackVector": "ADJACENT_NETWORK", "baseSeverity": "MEDIUM", "vectorString": "CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H", "integrityImpact": "NONE", "userInteraction": "NONE", "attackComplexity": "LOW", "availabilityImpact": "HIGH", "privilegesRequired": "NONE", "confidentialityImpact": "NONE"}, "impactScore": 3.6, "exploitabilityScore": 2.8}], "cvssMetricV40": [{"type": "Secondary", "source": "sirt@juniper.net", "cvssData": {"Safety": "NOT_DEFINED", "version": "4.0", "Recovery": "AUTOMATIC", "baseScore": 7.1, "Automatable": "YES", "attackVector": "ADJACENT", "baseSeverity": "HIGH", "valueDensity": "CONCENTRATED", "vectorString": "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/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", "exploitMaturity": "NOT_DEFINED", "providerUrgency": "AMBER", "userInteraction": "NONE", "attackComplexity": "LOW", "attackRequirements": "NONE", "privilegesRequired": "NONE", "subIntegrityImpact": "NONE", "vulnIntegrityImpact": "NONE", "integrityRequirement": "NOT_DEFINED", "modifiedAttackVector": "NOT_DEFINED", "subAvailabilityImpact": "LOW", "vulnAvailabilityImpact": "HIGH", "availabilityRequirement": "NOT_DEFINED", "modifiedUserInteraction": "NOT_DEFINED", "modifiedAttackComplexity": "NOT_DEFINED", "subConfidentialityImpact": "NONE", "vulnConfidentialityImpact": "NONE", "confidentialityRequirement": "NOT_DEFINED", "modifiedAttackRequirements": "NOT_DEFINED", "modifiedPrivilegesRequired": "NOT_DEFINED", "modifiedSubIntegrityImpact": "NOT_DEFINED", "modifiedVulnIntegrityImpact": "NOT_DEFINED", "vulnerabilityResponseEffort": "MODERATE", "modifiedSubAvailabilityImpact": "NOT_DEFINED", "modifiedVulnAvailabilityImpact": "NOT_DEFINED", "modifiedSubConfidentialityImpact": "NOT_DEFINED", "modifiedVulnConfidentialityImpact": "NOT_DEFINED"}}]}, "affected": [{"source": "sirt@juniper.net", "affectedData": [{"vendor": "Juniper Networks", "product": "Junos OS Evolved", "versions": [{"status": "affected", "version": "0", "lessThan": "21.4R3-S7-EVO", "versionType": "semver"}, {"status": "affected", "version": "22.2", "lessThan": "22.2R3-S4-EVO", "versionType": "semver"}, {"status": "affected", "version": "22.3", "lessThan": "22.3R3-S3-EVO", "versionType": "semver"}, {"status": "affected", "version": "22.4", "lessThan": "22.4R3-S2-EVO", "versionType": "semver"}, {"status": "affected", "version": "23.2", "lessThan": "23.2R2-S1-EVO", "versionType": "semver"}, {"status": "affected", "version": "23.4", "lessThan": "23.4R1-S2-EVO, 23.4R2-EVO", "versionType": "semver"}], "defaultStatus": "unaffected"}]}], "published": "2026-01-15T21:16:07.110", "references": [{"url": "https://kb.juniper.net/JSA106010", "tags": ["Vendor Advisory"], "source": "sirt@juniper.net"}, {"url": "https://supportportal.juniper.net/JSA106010", "tags": ["Vendor Advisory"], "source": "sirt@juniper.net"}], "vulnStatus": "Analyzed", "weaknesses": [{"type": "Secondary", "source": "sirt@juniper.net", "description": [{"lang": "en", "value": "CWE-682"}]}], "descriptions": [{"lang": "en", "value": "An Incorrect Calculation vulnerability in the Layer 2 Control\n\nProtocol \n\n Daemon (l2cpd) of Juniper Networks Junos OS Evolved allows an unauthenticated network-adjacent attacker flapping the management interface to cause the learning of new MACs over label-switched interfaces (LSI) to stop while generating a\u00a0flood of logs, resulting in high CPU usage.\n\nWhen the issue is seen, the following log message will be generated:\n\nop:1 flag:0x6 mac:xx:xx:xx:xx:xx:xx bd:2 ifl:13302 reason:0(REASON_NONE) i-op:6(INTRNL_OP_HW_FORCE_DELETE) status:10 lstatus:10 err:26(GETIFBD_VALIDATE_FAILED) err-reason 4(IFBD_VALIDATE_FAIL_EPOCH_MISMATCH) hw_wr:0x4 ctxsync:0 fwdsync:0 rtt-id:51 p_ifl:0 fwd_nh:0 svlbnh:0 event:- smask:0x100000000 dmask:0x0 mplsmask 0x1 act:0x5800 extf:0x0 pfe-id 0 hw-notif-ifl 13302 programmed-ifl 4294967295 pseudo-vtep underlay-ifl-idx 0 stack:GET_MAC, ALLOCATE_MAC, GET_IFL, GET_IFF, GET_IFBD, STOP, \n\n\nThis issue affects Junos OS Evolved:\u00a0\n\n * all versions before 21.4R3-S7-EVO,\u00a0\n * from 22.2 before 22.2R3-S4-EVO,\u00a0\n * from 22.3 before 22.3R3-S3-EVO,\u00a0\n * from 22.4 before 22.4R3-S2-EVO,\u00a0\n * from 23.2 before 23.2R2-S1-EVO,\u00a0\n * from 23.4 before 23.4R1-S2-EVO, 23.4R2-EVO."}, {"lang": "es", "value": "Una vulnerabilidad de c\u00e1lculo incorrecto en el demonio del protocolo de control de capa 2 (l2cpd) de Juniper Networks Junos OS Evolved permite a un atacante adyacente a la red no autenticado que alterna la interfaz de gesti\u00f3n detener el aprendizaje de nuevas MAC a trav\u00e9s de interfaces conmutadas por etiquetas (LSI) mientras genera una inundaci\u00f3n de registros, lo que resulta en un alto uso de la CPU.\n\nCuando se observa el problema, se generar\u00e1 el siguiente mensaje de registro:\n\nop:1 flag:0x6 mac:xx:xx:xx:xx:xx:xx bd:2 ifl:13302 reason:0(REASON_NONE) i-op:6(INTRNL_OP_HW_FORCE_DELETE) status:10 lstatus:10 err:26(GETIFBD_VALIDATE_FAILED) err-reason 4(IFBD_VALIDATE_FAIL_EPOCH_MISMATCH) hw_wr:0x4 ctxsync:0 fwdsync:0 rtt-id:51 p_ifl:0 fwd_nh:0 svlbnh:0 event:- smask:0x100000000 dmask:0x0 mplsmask 0x1 act:0x5800 extf:0x0 pfe-id 0 hw-notif-ifl 13302 programmed-ifl 4294967295 pseudo-vtep underlay-ifl-idx 0 stack:GET_MAC, ALLOCATE_MAC, GET_IFL, GET_IFF, GET_IFBD, STOP,\n\nEste problema afecta a Junos OS Evolved:\n\n * todas las versiones anteriores a 21.4R3-S7-EVO,\n * desde 22.2 anteriores a 22.2R3-S4-EVO,\n * desde 22.3 anteriores a 22.3R3-S3-EVO,\n * desde 22.4 anteriores a 22.4R3-S2-EVO,\n * desde 23.2 anteriores a 23.2R2-S1-EVO,\n * desde 23.4 anteriores a 23.4R1-S2-EVO, 23.4R2-EVO."}], "lastModified": "2026-06-17T10:19:08.587", "configurations": [{"nodes": [{"negate": false, "cpeMatch": [{"criteria": "cpe:2.3:o:juniper:junos_os_evolved:*:*:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "A51696D6-8503-4CBD-AD19-861E5BE94ED4", "versionEndExcluding": "21.4"}, {"criteria": "cpe:2.3:o:juniper:junos_os_evolved:21.4:-:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "2E907193-075E-45BC-9257-9607DB790D71"}, {"criteria": "cpe:2.3:o:juniper:junos_os_evolved:21.4:r1:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "8B73A41D-3FF5-4E53-83FF-74DF58E0D6C3"}, {"criteria": "cpe:2.3:o:juniper:junos_os_evolved:21.4:r1-s1:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "CEDF46A8-FC3A-4779-B695-2CA11D045AEB"}, {"criteria": 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