CVE-2026-88032 is a medium severity use after free flaw in MongoDB Java Driver, scored 5.9. The record does not name a fixed version. Check your installed version against the affected list below, then patch or restrict access until you can. The record does not flag it as exploited.
What's affected
- The reactive client-side encryption component of the MongoDB Java Driver.
- Only configurations that retrieve KMS credentials on demand.
Severity in the record: Medium (5.9), vector CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H. Weakness: CWE-416.
Fix: The record does not name a fixed version. Check the MongoDB Jira ticket JAVA-6276.
How to check if you're exposed
- List the driver version:
mvn dependency:tree -Dincludes=org.mongodborgradle dependencies | grep mongodb. - Check for use of the reactive streams driver with client-side encryption.
- Check whether KMS credentials are fetched on demand.
Run these on every host, image and build that could carry the component. Dependency files in repositories and base images in registries are easy to miss.
What to do now
- Confirm the version of every affected system using the checks above.
- Read the vendor advisory linked in Sources and note the fixed version for your release line.
- Schedule the update, starting with systems that face untrusted networks or hold the most sensitive data.
- In the meantime: review where cancellation can be triggered by remote callers, such as request timeouts.
- Record the change, then recheck the version to confirm it took effect.
Why it matters
When an encrypted operation is cancelled, native resources can be freed while the operation is still using them. That is CWE-416, use after free. The record says a party able to cause such a cancellation may terminate the host application process. The score is 5.9 because the attack complexity is high and the impact is on availability only.
The record's KEV flag is false, so this post makes no claim that the flaw is exploited in the wild. That can change, so recheck the CISA catalog from time to time.
Libraries like this often arrive as transitive dependencies, so the version in your lockfile may not be one you chose. Safeguard's free in-browser dependency scan can show whether the package is in a project, and reachability analysis helps separate code paths that call the weak function from those that never do.
The vector string in the record is a compact summary of how the flaw is reached and what it costs. AV is the attack vector (network, adjacent or local), PR is the privilege the attacker needs, and the C, I and A letters give the impact on confidentiality, integrity and availability. Read it against your own network layout rather than relying on the score alone.
After you patch
Patching is not the end of the job. Recheck the version on each system, because an upgrade that failed or rolled back looks the same as a success until someone looks. Keep the advisory link with your change record so the next reviewer can see why the update happened.
If you cannot patch soon, write down the reason, the compensating control you chose and a date to revisit. Exceptions without a date tend to become permanent.
Quick check
Does this affect the standard driver?
The record limits it to an affected reactive encryption configuration that retrieves KMS credentials on demand.
Sources
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MongoDB Jira: JAVA-6276
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Safeguard Gold: CVE-2026-88032
Last reviewed: 18 October 2026.
