CVE-2026-106433 Heap corruption via duplicate masterKey fields in MongoDB libmongocrypt
An authenticated attacker can cause heap corruption and potential code execution in MongoDB libmongocrypt by manipulating key vault documents with duplicate masterKey fields.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-106433?
CVE-2026-106433 is a high-severity memory corruption vulnerability in MongoDB libmongocrypt, published on 8 Oct 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Official description
Improper state management in MongoDB libmongocrypt can cause provider-specific data to be treated as an incompatible type when cleaning up a key document containing duplicate masterKey fields. An authenticated actor who can modify key vault documents, or a server that returns such a key document, can cause invalid memory access and invalid frees in the client process. This can terminate the application or corrupt process memory.
Weakness: CWE-843
Which versions are affected by CVE-2026-106433?
It affects 1 product.
Products include Mongodb Libmongocrypt.
How do I fix CVE-2026-106433?
Upgrade to a fixed version.
Upgrade to the fixed version. Memory-safe languages, compiler hardening and fuzzing prevent most new cases. More about Memory corruption.
Is CVE-2026-106433 being exploited?
There is no known exploitation of CVE-2026-106433 in the wild and no public exploit code.
Other vulnerabilities in MongoDB libmongocrypt
- CVE-2026-84971 Persistent client crash loop via undersized FLE2 insert-update ciphertext in decryption path
- CVE-2026-84962 Authenticated KMS request forgery via CRLF injection in GCP key identifier strings
- CVE-2026-81523 Cross-tenant database retargeting via dot/NUL injection in namespace strings in libmongocrypt
Sources
Also known as DEBIAN-CVE-2026-106433, UBUNTU-CVE-2026-106433.