CVE-2026-21918

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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."}], "lastModified": "2026-01-23T19:41:38.067", "configurations": [{"nodes": [{"negate": false, "cpeMatch": [{"criteria": "cpe:2.3:o:juniper:junos:*:*:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "57F66641-003B-49D6-A9B9-AB300CFE3C93", "versionEndExcluding": "22.4"}, {"criteria": "cpe:2.3:o:juniper:junos:22.4:-:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "1379EF30-AF04-4F98-8328-52A631F24737"}, {"criteria": "cpe:2.3:o:juniper:junos:22.4:r1:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "28E42A41-7965-456B-B0AF-9D3229CE4D4C"}, {"criteria": "cpe:2.3:o:juniper:junos:22.4:r1-s1:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "CB1A77D6-D3AD-481B-979C-8F778530B175"}, {"criteria": 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