CVE-2026-84971: Persistent client crash loop via undersized FLE2 insert-update ciphertext in decryption path
Medium · CVSS 6.5 (CVSS 3.1)EPSS 0.26%, 17th percentilePublished Updated Assigner: mongodb
Description
Improper handling of an unexpected value size in the decryption path of a client-side encryption library can cause a failed internal check that terminates the process using the library. A party able to place a suitably formed encrypted value where an application will decrypt it, or able to control the responses the application receives, may cause that application to stop running.
Vector CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H · CWE-617
Tracked companies
Mapped from the CVE’s affected-product data, NVD CPE matches, vendor advisories or package feeds. A mapping means the vendor’s software is named, not that its hosted service was exposed.
Status incidents that name it
No tracked status incident names this CVE.
Affected vendors and products
MongoDB: libmongocrypt
References
- CVE record on cve.org (opens in new tab)
- NVD entry (opens in new tab)
- jira.mongodb.org/browse/MONGOCRYPT-971 (opens in new tab)
- CVE records from the CVE Program (cve.org). CVE® is a registered trademark of The MITRE Corporation. (opens in new tab)
- This product uses data from the NVD API but is not endorsed or certified by the NVD. (opens in new tab)
- Known Exploited Vulnerabilities catalog from CISA. (opens in new tab)
- EPSS scores from FIRST (Exploit Prediction Scoring System). (opens in new tab)