CVE-2026-84971 — Persistent client crash loop via undersized FLE2 insert-update ciphertext in decryption path

CVE-2026-84971

Persistent client crash loop via undersized FLE2 insert-update ciphertext in decryption path PUBLISHED

Description (CNA)

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.

Affected (CNA)

Vendor / product	Versions
MongoDB / libmongocrypt	affected 1.7.0 before 1.20.4

CWE

CWE-617

References

https://jira.mongodb.org/browse/MONGOCRYPT-971

ADP enrichment

CISA-ADP

No English description supplied.

No references supplied.