{"id":"CVE-2026-81528","title":"A MongoDB C# driver document-replacement code path omits the element-name/shape validation that the equivalent write paths apply, so a value supplied as a replacement is forwarded to the server without neutralization of query-language sp…","summary":"A MongoDB C# driver document-replacement code path omits the element-name/shape validation that the equivalent write paths apply, so a value supplied as a replacement is forwarded to the server without neutralization of query-language sp…","severity":"medium","cvss":5.4,"cvssVector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N","cwe":["CWE-943"],"vendor":"mongodb","product":"c#_driver","affected":["c#_driver >= 2.10.0, < 3.11.1"],"patched":["c#_driver 3.11.1"],"published":"2026-08-27","updated":"2026-09-29","sourceUpdated":"2026-09-29T19:16:27.513","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-81528","references":[{"url":"https://jira.mongodb.org/browse/CSHARP-6158","label":"cna@mongodb.com"},{"url":"https://www.nuget.org/packages/MongoDB.Driver/3.11.1","label":"cna@mongodb.com"}],"tags":["nvd"],"epss":0.00273,"epssPercentile":0.17735,"ingestedAt":"2026-09-29T19:44:04.117Z","slug":"CVE-2026-81528","body":"## Overview\n\nA MongoDB C# driver document-replacement code path omits the element-name/shape validation that the equivalent write paths apply, so a value supplied as a replacement is forwarded to the server without neutralization of query-language special elements. An application that passes untrusted, loosely-typed input as a replacement value therefore allows that input to be interpreted by the database as update logic rather than as data, executing under the application's own database credentials. Applications using strongly-typed document mappings are not affected.\n\n## Affected\n\n- `c#_driver >= 2.10.0, < 3.11.1`\n\n## Remediation\n\nUpgrade past the affected range:\n\n- `c#_driver 3.11.1`","depth":"sunlit","depthScore":30,"depthScoreParts":{"impact":29.7,"likelihood":0.1,"exploitation":0,"ransomware":0},"changes":[]}