{"schemaVersion":3,"id":"CVE-2026-81527","aliases":[],"status":"published","duplicateOf":null,"title":null,"description":"A NoSQL/expression injection weakness exists in the LINQ-to-aggregation query translation layer of the MongoDB C# Driver, in both aggregation expression and query filter translation. When application-supplied values are embedded in certain query constructs, special elements contained within those values are not properly escaped before the resulting query is transmitted to the database, so portions of the value may be interpreted by the database as query logic rather than as data. A user able to supply values that an application incorporates into an affected query may thereby cause unintended data to be returned or query results to be altered.","dates":{"published":"2026-08-27T18:32:28.926Z","modified":"2026-08-28T15:46:55.682Z","reserved":null,"kevAdded":[],"kevDue":[]},"cvss":{"headline":{"score":6.9,"severity":"medium","version":"4.0","versionLabel":"v4.0","source":"CVE.org","vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N","computed":false,"selection":"backend-summary"},"metrics":[{"version":"4.0","versionLabel":"v4.0","source":"CVE.org","score":6.9,"severity":"medium","vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N","exploitability":null,"impact":null,"computed":false},{"version":"3.1","versionLabel":"v3.1","source":"CVE.org","score":6.5,"severity":"medium","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N","exploitability":null,"impact":null,"computed":false},{"version":"4.0","versionLabel":"v4.0","source":"NVD","score":6.9,"severity":"medium","vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N/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:X/R:X/V:X/RE:X/U:X","exploitability":null,"impact":null,"computed":false},{"version":"3.1","versionLabel":"v3.1","source":"NVD","score":6.5,"severity":"medium","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N","exploitability":null,"impact":null,"computed":false}]},"epss":{"probability":0.00306,"percentile":0.22142,"severity":"low","asOf":"2026-10-21T00:00:00.000Z","change":{"pp":0.12299999999999997,"baselineDate":"2026-09-21T00:00:00.000Z","baselineScore":0.00183},"history":[{"date":"2026-09-14T00:00:00.000Z","score":0.00183,"percentile":null},{"date":"2026-09-15T00:00:00.000Z","score":0.00183,"percentile":null},{"date":"2026-09-16T00:00:00.000Z","score":0.00183,"percentile":null},{"date":"2026-09-17T00:00:00.000Z","score":0.00183,"percentile":null},{"date":"2026-09-18T00:00:00.000Z","score":0.00183,"percentile":null},{"date":"2026-09-19T00:00:00.000Z","score":0.00183,"percentile":null},{"date":"2026-09-20T00:00:00.000Z","score":0.00183,"percentile":null},{"date":"2026-09-21T00:00:00.000Z","score":0.00183,"percentile":null},{"date":"2026-09-22T00:00:00.000Z","score":0.00183,"percentile":null},{"date":"2026-09-23T00:00:00.000Z","score":0.00183,"percentile":null},{"date":"2026-09-24T00:00:00.000Z","score":0.00306,"percentile":null},{"date":"2026-09-25T00:00:00.000Z","score":0.00306,"percentile":null},{"date":"2026-09-26T00:00:00.000Z","score":0.00306,"percentile":null},{"date":"2026-09-27T00:00:00.000Z","score":0.00306,"percentile":null},{"date":"2026-09-28T00:00:00.000Z","score":0.00306,"percentile":null},{"date":"2026-09-29T00:00:00.000Z","score":0.00306,"percentile":null},{"date":"2026-09-30T00:00:00.000Z","score":0.00306,"percentile":null},{"date":"2026-10-01T00:00:00.000Z","score":0.00306,"percentile":null},{"date":"2026-10-02T00:00:00.000Z","score":0.00306,"percentile":null},{"date":"2026-10-03T00:00:00.000Z","score":0.00306,"percentile":null},{"date":"2026-10-04T00:00:00.000Z","score":0.00306,"percentile":null},{"date":"2026-10-05T00:00:00.000Z","score":0.00306,"percentile":null},{"date":"2026-10-06T00:00:00.000Z","score":0.00306,"percentile":null},{"date":"2026-10-07T00:00:00.000Z","score":0.00306,"percentile":null},{"date":"2026-10-08T00:00:00.000Z","score":0.00306,"percentile":null},{"date":"2026-10-09T00:00:00.000Z","score":0.00306,"percentile":null},{"date":"2026-10-10T00:00:00.000Z","score":0.00306,"percentile":null},{"date":"2026-10-11T00:00:00.000Z","score":0.00306,"percentile":null},{"date":"2026-10-12T00:00:00.000Z","score":0.00306,"percentile":null},{"date":"2026-10-13T00:00:00.000Z","score":0.00306,"percentile":null},{"date":"2026-10-14T00:00:00.000Z","score":0.00306,"percentile":null},{"date":"2026-10-15T00:00:00.000Z","score":0.00306,"percentile":null},{"date":"2026-10-16T00:00:00.000Z","score":0.00306,"percentile":null},{"date":"2026-10-17T00:00:00.000Z","score":0.00306,"percentile":null},{"date":"2026-10-18T00:00:00.000Z","score":0.00306,"percentile":null},{"date":"2026-10-19T00:00:00.000Z","score":0.00306,"percentile":null},{"date":"2026-10-20T00:00:00.000Z","score":0.00306,"percentile":null},{"date":"2026-10-21T00:00:00.000Z","score":0.00306,"percentile":0.22142}],"last30":[{"date":"2026-09-21T00:00:00.000Z","score":0.00183,"percentile":null},{"date":"2026-09-22T00:00:00.000Z","score":0.00183,"percentile":null},{"date":"2026-09-23T00:00:00.000Z","score":0.00183,"percentile":null},{"date":"2026-09-24T00:00:00.000Z","score":0.00306,"percentile":null},{"date":"2026-09-25T00:00:00.000Z","score":0.00306,"percentile":null},{"date":"2026-09-26T00:00:00.000Z","score":0.00306,"percentile":null},{"date":"2026-09-27T00:00:00.000Z","score":0.00306,"percentile":null},{"date":"2026-09-28T00:00:00.000Z","score":0.00306,"percentile":null},{"date":"2026-09-29T00:00:00.000Z","score":0.00306,"percentile":null},{"date":"2026-09-30T00:00:00.000Z","score":0.00306,"percentile":null},{"date":"2026-10-01T00:00:00.000Z","score":0.00306,"percentile":null},{"date":"2026-10-02T00:00:00.000Z","score":0.00306,"percentile":null},{"date":"2026-10-03T00:00:00.000Z","score":0.00306,"percentile":null},{"date":"2026-10-04T00:00:00.000Z","score":0.00306,"percentile":null},{"date":"2026-10-05T00:00:00.000Z","score":0.00306,"percentile":null},{"date":"2026-10-06T00:00:00.000Z","score":0.00306,"percentile":null},{"date":"2026-10-07T00:00:00.000Z","score":0.00306,"percentile":null},{"date":"2026-10-08T00:00:00.000Z","score":0.00306,"percentile":null},{"date":"2026-10-09T00:00:00.000Z","score":0.00306,"percentile":null},{"date":"2026-10-10T00:00:00.000Z","score":0.00306,"percentile":null},{"date":"2026-10-11T00:00:00.000Z","score":0.00306,"percentile":null},{"date":"2026-10-12T00:00:00.000Z","score":0.00306,"percentile":null},{"date":"2026-10-13T00:00:00.000Z","score":0.00306,"percentile":null},{"date":"2026-10-14T00:00:00.000Z","score":0.00306,"percentile":null},{"date":"2026-10-15T00:00:00.000Z","score":0.00306,"percentile":null},{"date":"2026-10-16T00:00:00.000Z","score":0.00306,"percentile":null},{"date":"2026-10-17T00:00:00.000Z","score":0.00306,"percentile":null},{"date":"2026-10-18T00:00:00.000Z","score":0.00306,"percentile":null},{"date":"2026-10-19T00:00:00.000Z","score":0.00306,"percentile":null},{"date":"2026-10-20T00:00:00.000Z","score":0.00306,"percentile":null},{"date":"2026-10-21T00:00:00.000Z","score":0.00306,"percentile":0.22142}]},"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":[{"id":"CWE-943","name":"Improper Neutralization of Special Elements in Data Query Logic","description":"The product generates a query intended to access or manipulate data in a data store such as a database, but it does not neutralize or incorrectly neutralizes special elements that can modify the intended logic of the query.","type":"weakness","status":"Incomplete","abstraction":"Class","likelihoodOfExploit":null,"url":"https://cwe.mitre.org/data/definitions/943.html"}],"affected":[{"vendor":"mongodb","product":"c_driver","name":"c driver","label":"c_driver","ecosystem":null,"cpePart":"a","purl":null,"purlType":null,"versions":[{"text":"≥ 2.14.0, < 3.11.1","noFixRecorded":false,"fixedIn":null},{"text":"≥ 2.10.0, < 3.11.1","noFixRecorded":false,"fixedIn":null}],"versionsText":"≥ 2.14.0, < 3.11.1 | ≥ 2.10.0, < 3.11.1","eol":null,"hubHref":"/vendor/mongodb/c_driver"}],"affectedCount":1,"eol":{"hasEol":false,"count":0},"references":[{"url":"https://jira.mongodb.org/browse/CSHARP-6156","label":"jira.mongodb.org/browse/CSHARP-6156","hostname":"jira.mongodb.org","tags":["Vendor Advisory"]},{"url":"https://www.nuget.org/packages/MongoDB.Driver/3.11.1","label":"www.nuget.org/packages/MongoDB.Driver/3.11.1","hostname":"www.nuget.org","tags":["Product"]}],"lineage":{"upstream":[],"downstream":[],"duplicates":[],"related":[]},"timeline":[{"kind":"published","date":"2026-08-27T18:32:28.926Z","label":"Published","detail":"Vulnerability first disclosed.","source":null},{"kind":"modified","date":"2026-08-28T15:46:55.682Z","label":"Last modified","detail":"Vulnerability information updated.","source":null}],"risk":{"score":28,"level":"medium","profile":"Default","thresholds":{"critical":75,"high":50,"medium":25,"low":10}},"meta":{"dataAsOf":"2026-10-21T18:33:15.525Z","stale":false,"partial":false}}