FKIE_CVE-2026-21918
Vulnerability from fkie_nvd - Published: 2026-01-15 21:16 - Updated: 2026-01-23 19:41
Severity ?
Summary
A Double Free vulnerability in the flow processing daemon (flowd) of Juniper Networks Junos OS on SRX and MX Series allows an unauthenticated, network-based attacker to cause a Denial-of-Service (DoS). On all SRX and MX Series platforms, when during TCP session establishment a specific sequence of packets is encountered a double free happens. This causes flowd to crash and the respective FPC to restart.
This issue affects Junos OS on SRX and MX Series:
* all versions before 22.4R3-S7,
* 23.2 versions before 23.2R2-S3,
* 23.4 versions before 23.4R2-S4,
* 24.2 versions before 24.2R2.
References
| URL | Tags | ||
|---|---|---|---|
| sirt@juniper.net | https://kb.juniper.net/JSA106018 | Vendor Advisory | |
| sirt@juniper.net | https://supportportal.juniper.net/JSA106018 | Vendor Advisory |
Impacted products
{
"configurations": [
{
"nodes": [
{
"cpeMatch": [
{
"criteria": "cpe:2.3:o:juniper:junos:*:*:*:*:*:*:*:*",
"matchCriteriaId": "57F66641-003B-49D6-A9B9-AB300CFE3C93",
"versionEndExcluding": "22.4",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:juniper:junos:22.4:-:*:*:*:*:*:*",
"matchCriteriaId": "1379EF30-AF04-4F98-8328-52A631F24737",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:juniper:junos:22.4:r1:*:*:*:*:*:*",
"matchCriteriaId": "28E42A41-7965-456B-B0AF-9D3229CE4D4C",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:juniper:junos:22.4:r1-s1:*:*:*:*:*:*",
"matchCriteriaId": "CB1A77D6-D3AD-481B-979C-8F778530B175",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:juniper:junos:22.4:r1-s2:*:*:*:*:*:*",
"matchCriteriaId": "3A064B6B-A99B-4D8D-A62D-B00C7870BC30",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:juniper:junos:22.4:r2:*:*:*:*:*:*",
"matchCriteriaId": "40813417-A938-4F74-A419-8C5188A35486",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:juniper:junos:22.4:r2-s1:*:*:*:*:*:*",
"matchCriteriaId": "7FC1BA1A-DF0E-4B15-86BA-24C60E546732",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:juniper:junos:22.4:r2-s2:*:*:*:*:*:*",
"matchCriteriaId": "EBB967BF-3495-476D-839A-9DBFCBE69F91",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:juniper:junos:22.4:r3:*:*:*:*:*:*",
"matchCriteriaId": "7E5688D6-DCA4-4550-9CD1-A3D792252129",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:juniper:junos:22.4:r3-s1:*:*:*:*:*:*",
"matchCriteriaId": "8494546C-00EA-49B6-B6FA-FDE42CA5B1FA",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:juniper:junos:22.4:r3-s2:*:*:*:*:*:*",
"matchCriteriaId": "8BB98579-FA33-4E41-A162-A46E9709FBD3",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:juniper:junos:22.4:r3-s3:*:*:*:*:*:*",
"matchCriteriaId": "08E2562F-FB18-4347-8497-7D61B8157EBB",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:juniper:junos:22.4:r3-s4:*:*:*:*:*:*",
"matchCriteriaId": "494D1D96-1DA2-4B0A-9536-1B5A4FDFCA09",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:juniper:junos:22.4:r3-s5:*:*:*:*:*:*",
"matchCriteriaId": "60A1E37B-1990-44D9-87FE-300678243BE2",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:juniper:junos:22.4:r3-s6:*:*:*:*:*:*",
"matchCriteriaId": "D306ED88-8700-4FD4-8919-3C85728C04C3",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:juniper:junos:23.2:-:*:*:*:*:*:*",
"matchCriteriaId": "1A78CC80-E8B1-4CDA-BB35-A61833657FA7",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:juniper:junos:23.2:r1:*:*:*:*:*:*",
"matchCriteriaId": "4B3B2FE1-C228-46BE-AC76-70C2687050AE",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:juniper:junos:23.2:r1-s1:*:*:*:*:*:*",
"matchCriteriaId": "F1B16FF0-900F-4AEE-B670-A537139F6909",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:juniper:junos:23.2:r1-s2:*:*:*:*:*:*",
"matchCriteriaId": "B227E831-30FF-4BE1-B8B2-31829A5610A6",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:juniper:junos:23.2:r2:*:*:*:*:*:*",
"matchCriteriaId": "1ADA814B-EF98-45B1-AF7A-0C89688F7CA5",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:juniper:junos:23.2:r2-s1:*:*:*:*:*:*",
"matchCriteriaId": "A6FB32DF-D062-4FB9-8777-452978BEC7B7",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:juniper:junos:23.2:r2-s2:*:*:*:*:*:*",
"matchCriteriaId": "B3B6C811-5C10-4486-849D-5559B592350A",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:juniper:junos:23.4:-:*:*:*:*:*:*",
"matchCriteriaId": "78481ABC-3620-410D-BC78-334657E0BB75",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:juniper:junos:23.4:r1:*:*:*:*:*:*",
"matchCriteriaId": "BE8A5BA3-87BD-473A-B229-2AAB2C797005",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:juniper:junos:23.4:r1-s1:*:*:*:*:*:*",
"matchCriteriaId": "8B74AC3E-8FC9-400A-A176-4F7F21F10756",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:juniper:junos:23.4:r1-s2:*:*:*:*:*:*",
"matchCriteriaId": "CB2D1FCE-8019-4CE1-BA45-D62F91AF7B51",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:juniper:junos:23.4:r2:*:*:*:*:*:*",
"matchCriteriaId": "175CCB13-76C0-44A4-A71D-41E22B92EB23",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:juniper:junos:23.4:r2-s1:*:*:*:*:*:*",
"matchCriteriaId": "166BFDB3-1945-4949-BC2B-E18442FF2E4D",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:juniper:junos:23.4:r2-s2:*:*:*:*:*:*",
"matchCriteriaId": "5923610F-878C-48CA-8B5D-9C609E4DD4DB",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:juniper:junos:23.4:r2-s3:*:*:*:*:*:*",
"matchCriteriaId": "A7C207E3-0252-4192-8E8C-E2ED2831B4F4",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:juniper:junos:24.2:-:*:*:*:*:*:*",
"matchCriteriaId": "89524D6D-0B22-4952-AD8E-8072C5A05D5C",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:juniper:junos:24.2:r1:*:*:*:*:*:*",
"matchCriteriaId": "AD69A194-1B03-44EA-8092-79BD10C6F729",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:juniper:junos:24.2:r1-s1:*:*:*:*:*:*",
"matchCriteriaId": "8463ADB4-B8A7-4D63-97A9-232ED713A21C",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:juniper:junos:24.2:r1-s2:*:*:*:*:*:*",
"matchCriteriaId": "FE68337F-106E-4317-A5B6-292B0159F577",
"vulnerable": true
}
],
"negate": false,
"operator": "OR"
},
{
"cpeMatch": [
{
"criteria": "cpe:2.3:h:juniper:mx10004:-:*:*:*:*:*:*:*",
"matchCriteriaId": "84F7BB7E-3A52-4C23-A4D2-50E75C912AFC",
"vulnerable": false
},
{
"criteria": "cpe:2.3:h:juniper:mx10008:-:*:*:*:*:*:*:*",
"matchCriteriaId": "D6F0EA2F-BF7E-45D0-B2B4-8A7B67A9475A",
"vulnerable": false
},
{
"criteria": "cpe:2.3:h:juniper:mx2008:-:*:*:*:*:*:*:*",
"matchCriteriaId": "2FEF33EB-B2E0-42EF-A1BB-D41021B6D08F",
"vulnerable": false
},
{
"criteria": "cpe:2.3:h:juniper:mx2010:-:*:*:*:*:*:*:*",
"matchCriteriaId": "27175D9A-CA2C-4218-8042-835E25DFCA43",
"vulnerable": false
},
{
"criteria": "cpe:2.3:h:juniper:mx2020:-:*:*:*:*:*:*:*",
"matchCriteriaId": "00C7FC57-8ACF-45AA-A227-7E3B350FD24F",
"vulnerable": false
},
{
"criteria": "cpe:2.3:h:juniper:mx204:-:*:*:*:*:*:*:*",
"matchCriteriaId": "2754C2DF-DF6E-4109-9463-38B4E0465B77",
"vulnerable": false
},
{
"criteria": "cpe:2.3:h:juniper:mx240:-:*:*:*:*:*:*:*",
"matchCriteriaId": "F4A26704-A6A4-4C4F-9E12-A0A0259491EF",
"vulnerable": false
},
{
"criteria": "cpe:2.3:h:juniper:mx304:-:*:*:*:*:*:*:*",
"matchCriteriaId": "3F7FB0CC-624D-4AB9-A7AC-BB19838C3B22",
"vulnerable": false
},
{
"criteria": "cpe:2.3:h:juniper:mx480:-:*:*:*:*:*:*:*",
"matchCriteriaId": "104858BD-D31D-40E0-8524-2EC311F10EAC",
"vulnerable": false
},
{
"criteria": "cpe:2.3:h:juniper:mx960:-:*:*:*:*:*:*:*",
"matchCriteriaId": "B5E08E1E-0FE4-4294-9497-BBFFECA2A220",
"vulnerable": false
},
{
"criteria": "cpe:2.3:h:juniper:srx1500:-:*:*:*:*:*:*:*",
"matchCriteriaId": "2CEBF85C-736A-4E7D-956A-3E8210D4F70B",
"vulnerable": false
},
{
"criteria": "cpe:2.3:h:juniper:srx1600:-:*:*:*:*:*:*:*",
"matchCriteriaId": "4AE06B18-BFB5-4029-A05D-386CFBFBF683",
"vulnerable": false
},
{
"criteria": "cpe:2.3:h:juniper:srx2300:-:*:*:*:*:*:*:*",
"matchCriteriaId": "48A1DCCD-208C-46D9-8E14-89592B49AB9A",
"vulnerable": false
},
{
"criteria": "cpe:2.3:h:juniper:srx300:-:*:*:*:*:*:*:*",
"matchCriteriaId": "BB5AB24B-2B43-43DD-AE10-F758B4B19F2A",
"vulnerable": false
},
{
"criteria": "cpe:2.3:h:juniper:srx320:-:*:*:*:*:*:*:*",
"matchCriteriaId": "80F9DC32-5ADF-4430-B1A6-357D0B29DB78",
"vulnerable": false
},
{
"criteria": "cpe:2.3:h:juniper:srx340:-:*:*:*:*:*:*:*",
"matchCriteriaId": "8B82D4C4-7A65-409A-926F-33C054DCBFBA",
"vulnerable": false
},
{
"criteria": "cpe:2.3:h:juniper:srx345:-:*:*:*:*:*:*:*",
"matchCriteriaId": "CE535749-F4CE-4FFA-B23D-BF09C92481E5",
"vulnerable": false
},
{
"criteria": "cpe:2.3:h:juniper:srx380:-:*:*:*:*:*:*:*",
"matchCriteriaId": "2305DA9D-E6BA-48F4-80CF-9E2DE7661B2F",
"vulnerable": false
},
{
"criteria": "cpe:2.3:h:juniper:srx4100:-:*:*:*:*:*:*:*",
"matchCriteriaId": "3AA8999C-8AE4-416F-BA2A-B1A21F33B4D7",
"vulnerable": false
},
{
"criteria": "cpe:2.3:h:juniper:srx4120:-:*:*:*:*:*:*:*",
"matchCriteriaId": "E5942B6E-AFC7-40E4-8007-68C804BD52E3",
"vulnerable": false
},
{
"criteria": "cpe:2.3:h:juniper:srx4200:-:*:*:*:*:*:*:*",
"matchCriteriaId": "CCC5F6F5-4347-49D3-909A-27A3A96D36C9",
"vulnerable": false
},
{
"criteria": "cpe:2.3:h:juniper:srx4300:-:*:*:*:*:*:*:*",
"matchCriteriaId": "826F893F-7B06-43B5-8653-A8D9794C052E",
"vulnerable": false
},
{
"criteria": "cpe:2.3:h:juniper:srx4600:-:*:*:*:*:*:*:*",
"matchCriteriaId": "56BA6B86-D3F4-4496-AE46-AC513C6560FA",
"vulnerable": false
},
{
"criteria": "cpe:2.3:h:juniper:srx4700:-:*:*:*:*:*:*:*",
"matchCriteriaId": "462CFD52-D3E2-4F7A-98AC-C589D2420556",
"vulnerable": false
},
{
"criteria": "cpe:2.3:h:juniper:srx5400:-:*:*:*:*:*:*:*",
"matchCriteriaId": "2FDDC897-747F-44DD-9599-7266F9B5B7B1",
"vulnerable": false
},
{
"criteria": "cpe:2.3:h:juniper:srx5600:-:*:*:*:*:*:*:*",
"matchCriteriaId": "68CA098D-CBE4-4E62-9EC0-43E1B6098710",
"vulnerable": false
},
{
"criteria": "cpe:2.3:h:juniper:srx5800:-:*:*:*:*:*:*:*",
"matchCriteriaId": "66F474D4-79B6-4525-983C-9A9011BD958B",
"vulnerable": false
}
],
"negate": false,
"operator": "OR"
}
],
"operator": "AND"
}
],
"cveTags": [],
"descriptions": [
{
"lang": "en",
"value": "A Double Free vulnerability in the flow processing daemon (flowd) of Juniper Networks Junos OS on SRX and MX Series allows an unauthenticated, network-based attacker to cause a Denial-of-Service (DoS). On all SRX and MX Series platforms, when during TCP session establishment a specific sequence of packets is encountered a double free happens. This causes flowd to crash and the respective FPC to restart.\n\n\n\n\n\nThis issue affects Junos OS on SRX and MX Series:\n\n\n\n * all versions before 22.4R3-S7,\n * 23.2 versions before 23.2R2-S3,\n * 23.4 versions before 23.4R2-S4,\n * 24.2 versions before 24.2R2."
}
],
"id": "CVE-2026-21918",
"lastModified": "2026-01-23T19:41:38.067",
"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": "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/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:X/RE:M/U:X",
"version": "4.0",
"vulnAvailabilityImpact": "HIGH",
"vulnConfidentialityImpact": "NONE",
"vulnIntegrityImpact": "NONE",
"vulnerabilityResponseEffort": "MODERATE"
},
"source": "sirt@juniper.net",
"type": "Secondary"
}
]
},
"published": "2026-01-15T21:16:08.050",
"references": [
{
"source": "sirt@juniper.net",
"tags": [
"Vendor Advisory"
],
"url": "https://kb.juniper.net/JSA106018"
},
{
"source": "sirt@juniper.net",
"tags": [
"Vendor Advisory"
],
"url": "https://supportportal.juniper.net/JSA106018"
}
],
"sourceIdentifier": "sirt@juniper.net",
"vulnStatus": "Analyzed",
"weaknesses": [
{
"description": [
{
"lang": "en",
"value": "CWE-415"
}
],
"source": "sirt@juniper.net",
"type": "Primary"
}
]
}
Loading…
Loading…
Sightings
| Author | Source | Type | Date |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or observed by the user.
- Confirmed: The vulnerability has been validated from an analyst's perspective.
- Published Proof of Concept: A public proof of concept is available for this vulnerability.
- Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
- Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
- Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
- Not confirmed: The user expressed doubt about the validity of the vulnerability.
- Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.
Loading…
Loading…