{"schemaVersion":3,"id":"CVE-2025-12978","aliases":[],"status":"published","duplicateOf":null,"title":null,"description":"Fluent Bit in_http, in_splunk, and in_elasticsearch input plugins contain a flaw in the tag_key validation logic that fails to enforce exact key-length matching. This allows crafted inputs where a tag prefix is incorrectly treated as a full match. A remote attacker with authenticated or exposed access to these input endpoints can exploit this behavior to manipulate tags and redirect records to unintended destinations. This compromises the authenticity of ingested logs and can allow injection of forged data, alert flooding and routing manipulation.","dates":{"published":"2025-11-24T14:42:06.305Z","modified":"2026-01-07T15:36:44.975Z","reserved":null,"kevAdded":[],"kevDue":[]},"cvss":{"headline":{"score":5.4,"severity":"medium","version":"3.1","versionLabel":"v3.1","source":"CVE.org","vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:L","computed":false,"selection":"backend-summary"},"metrics":[{"version":"3.1","versionLabel":"v3.1","source":"CVE.org","score":5.4,"severity":"medium","vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:L","exploitability":null,"impact":null,"computed":false},{"version":"3.1","versionLabel":"v3.1","source":"NVD","score":5.4,"severity":"medium","vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:L","exploitability":null,"impact":null,"computed":false}]},"epss":{"probability":0.00393,"percentile":0.32267,"severity":"low","asOf":"2026-10-21T00:00:00.000Z","change":{"pp":0,"baselineDate":"2026-09-21T00:00:00.000Z","baselineScore":0.00393},"history":[{"date":"2026-09-14T00:00:00.000Z","score":0.00393,"percentile":null},{"date":"2026-09-15T00:00:00.000Z","score":0.00393,"percentile":null},{"date":"2026-09-16T00:00:00.000Z","score":0.00393,"percentile":null},{"date":"2026-09-17T00:00:00.000Z","score":0.00393,"percentile":null},{"date":"2026-09-18T00:00:00.000Z","score":0.00393,"percentile":null},{"date":"2026-09-19T00:00:00.000Z","score":0.00393,"percentile":null},{"date":"2026-09-20T00:00:00.000Z","score":0.00393,"percentile":null},{"date":"2026-09-21T00:00:00.000Z","score":0.00393,"percentile":null},{"date":"2026-09-22T00:00:00.000Z","score":0.00393,"percentile":null},{"date":"2026-09-23T00:00:00.000Z","score":0.00393,"percentile":null},{"date":"2026-09-24T00:00:00.000Z","score":0.00393,"percentile":null},{"date":"2026-09-25T00:00:00.000Z","score":0.00393,"percentile":null},{"date":"2026-09-26T00:00:00.000Z","score":0.00393,"percentile":null},{"date":"2026-09-27T00:00:00.000Z","score":0.00393,"percentile":null},{"date":"2026-09-28T00:00:00.000Z","score":0.00393,"percentile":null},{"date":"2026-09-29T00:00:00.000Z","score":0.00393,"percentile":null},{"date":"2026-09-30T00:00:00.000Z","score":0.00393,"percentile":null},{"date":"2026-10-01T00:00:00.000Z","score":0.00393,"percentile":null},{"date":"2026-10-02T00:00:00.000Z","score":0.00393,"percentile":null},{"date":"2026-10-03T00:00:00.000Z","score":0.00393,"percentile":null},{"date":"2026-10-04T00:00:00.000Z","score":0.00393,"percentile":null},{"date":"2026-10-05T00:00:00.000Z","score":0.00393,"percentile":null},{"date":"2026-10-06T00:00:00.000Z","score":0.00393,"percentile":null},{"date":"2026-10-07T00:00:00.000Z","score":0.00393,"percentile":null},{"date":"2026-10-08T00:00:00.000Z","score":0.00393,"percentile":null},{"date":"2026-10-09T00:00:00.000Z","score":0.00393,"percentile":null},{"date":"2026-10-10T00:00:00.000Z","score":0.00393,"percentile":null},{"date":"2026-10-11T00:00:00.000Z","score":0.00393,"percentile":null},{"date":"2026-10-12T00:00:00.000Z","score":0.00393,"percentile":null},{"date":"2026-10-13T00:00:00.000Z","score":0.00393,"percentile":null},{"date":"2026-10-14T00:00:00.000Z","score":0.00393,"percentile":null},{"date":"2026-10-15T00:00:00.000Z","score":0.00393,"percentile":null},{"date":"2026-10-16T00:00:00.000Z","score":0.00393,"percentile":null},{"date":"2026-10-17T00:00:00.000Z","score":0.00393,"percentile":null},{"date":"2026-10-18T00:00:00.000Z","score":0.00393,"percentile":null},{"date":"2026-10-19T00:00:00.000Z","score":0.00393,"percentile":null},{"date":"2026-10-20T00:00:00.000Z","score":0.00393,"percentile":null},{"date":"2026-10-21T00:00:00.000Z","score":0.00393,"percentile":0.32267}],"last30":[{"date":"2026-09-21T00:00:00.000Z","score":0.00393,"percentile":null},{"date":"2026-09-22T00:00:00.000Z","score":0.00393,"percentile":null},{"date":"2026-09-23T00:00:00.000Z","score":0.00393,"percentile":null},{"date":"2026-09-24T00:00:00.000Z","score":0.00393,"percentile":null},{"date":"2026-09-25T00:00:00.000Z","score":0.00393,"percentile":null},{"date":"2026-09-26T00:00:00.000Z","score":0.00393,"percentile":null},{"date":"2026-09-27T00:00:00.000Z","score":0.00393,"percentile":null},{"date":"2026-09-28T00:00:00.000Z","score":0.00393,"percentile":null},{"date":"2026-09-29T00:00:00.000Z","score":0.00393,"percentile":null},{"date":"2026-09-30T00:00:00.000Z","score":0.00393,"percentile":null},{"date":"2026-10-01T00:00:00.000Z","score":0.00393,"percentile":null},{"date":"2026-10-02T00:00:00.000Z","score":0.00393,"percentile":null},{"date":"2026-10-03T00:00:00.000Z","score":0.00393,"percentile":null},{"date":"2026-10-04T00:00:00.000Z","score":0.00393,"percentile":null},{"date":"2026-10-05T00:00:00.000Z","score":0.00393,"percentile":null},{"date":"2026-10-06T00:00:00.000Z","score":0.00393,"percentile":null},{"date":"2026-10-07T00:00:00.000Z","score":0.00393,"percentile":null},{"date":"2026-10-08T00:00:00.000Z","score":0.00393,"percentile":null},{"date":"2026-10-09T00:00:00.000Z","score":0.00393,"percentile":null},{"date":"2026-10-10T00:00:00.000Z","score":0.00393,"percentile":null},{"date":"2026-10-11T00:00:00.000Z","score":0.00393,"percentile":null},{"date":"2026-10-12T00:00:00.000Z","score":0.00393,"percentile":null},{"date":"2026-10-13T00:00:00.000Z","score":0.00393,"percentile":null},{"date":"2026-10-14T00:00:00.000Z","score":0.00393,"percentile":null},{"date":"2026-10-15T00:00:00.000Z","score":0.00393,"percentile":null},{"date":"2026-10-16T00:00:00.000Z","score":0.00393,"percentile":null},{"date":"2026-10-17T00:00:00.000Z","score":0.00393,"percentile":null},{"date":"2026-10-18T00:00:00.000Z","score":0.00393,"percentile":null},{"date":"2026-10-19T00:00:00.000Z","score":0.00393,"percentile":null},{"date":"2026-10-20T00:00:00.000Z","score":0.00393,"percentile":null},{"date":"2026-10-21T00:00:00.000Z","score":0.00393,"percentile":0.32267}]},"kev":{"state":"not-listed","entries":[],"listedCount":0,"totalCatalogs":3,"catalogs":[{"source":"cisa","label":"CISA","listed":false,"entry":null},{"source":"enisa","label":"ENISA","listed":false,"entry":null},{"source":"circl","label":"CIRCL","listed":false,"entry":null}]},"ransomware":{"state":"none-recorded","sources":[]},"exploits":[],"exploitCount":0,"weaknesses":[],"affected":[{"vendor":"fluentbit","product":"fluent bit","name":"Fluent Bit","label":"fluent bit","ecosystem":null,"cpePart":"a","purl":null,"purlType":null,"versions":[{"text":"< 4.0.12","noFixRecorded":false,"fixedIn":null}],"versionsText":"< 4.0.12","eol":{"isEol":null,"eolDate":null,"matchMethod":"name_exact","cycle":null,"product":{"name":"fluent-bit","label":"Fluent Bit","category":"server-app"}},"hubHref":"/vendor/fluentbit/fluent_bit"},{"vendor":"treasuredata","product":"fluent_bit","name":"fluent bit","label":"fluent_bit","ecosystem":null,"cpePart":"a","purl":null,"purlType":null,"versions":[{"text":"4.1.0","noFixRecorded":false,"fixedIn":null}],"versionsText":"4.1.0","eol":{"isEol":true,"eolDate":"2026-02-11T00:00:00.000Z","matchMethod":"name_exact","cycle":{"name":"4.1","label":"4.1","eolFrom":"2026-02-11T00:00:00.000Z","isLts":false,"isMaintained":false,"latestVersion":"4.1.2"},"product":{"name":"fluent-bit","label":"Fluent Bit","category":"server-app"}},"hubHref":"/vendor/treasuredata/fluent_bit"}],"affectedCount":2,"eol":{"hasEol":true,"count":1},"references":[{"url":"https://fluentbit.io/announcements/v4.1.0/","label":"fluentbit.io/announcements/v4.1.0/","hostname":"fluentbit.io","tags":["Release Notes"]}],"lineage":{"upstream":[],"downstream":[],"duplicates":[],"related":[]},"timeline":[{"kind":"published","date":"2025-11-24T14:42:06.305Z","label":"Published","detail":"Vulnerability first disclosed.","source":null},{"kind":"modified","date":"2026-01-07T15:36:44.975Z","label":"Last modified","detail":"Vulnerability information updated.","source":null}],"risk":{"score":22,"level":"low","profile":"Default","thresholds":{"critical":75,"high":50,"medium":25,"low":10}},"meta":{"dataAsOf":"2026-10-21T16:36:57.280Z","stale":false,"partial":false}}