Medium · published September 10, 2026
A use-after-free in the reactive client-side encryption component of the MongoDB Java Driver can cause native resources to be freed while an affected encrypted operation is still using them when the operation is cancelled. A party able to cause such an operation to be cancelled may cause the hosting application process to terminate. Reaching the issue requires an affected reactive encryption configuration that retrieves KMS credentials on demand.
| Product | Versions | Fixed in |
|---|---|---|
| mongodb/java_driver | ≥ 4.2.0, < 5.11.1 | 5.11.1 |