CVE-2026-84971
Persistent client crash loop via undersized FLE2 insert-update ciphertext in decryption path
CVSS Score
6.5
EPSS Score
0.0%
EPSS Percentile
0th
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.
| CWE | CWE-617 |
| Vendor | mongodb |
| Product | libmongocrypt |
| Ecosystems | |
| Industries | Technology |
| Published | Sep 3, 2026 |
| Last Updated | Sep 3, 2026 |
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CVSS v3 Breakdown
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H Attack Vector
Network
Attack Complexity
Low
Privileges Required
Low
User Interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High
Affected Versions
MongoDB / libmongocrypt
1.7.0 < 1.20.4