Mongodb Libmongocrypt vulnerabilities

CVE-2026-106434 Medium · 4.3 CWE-354 Oct 8, 2026

Unrecognized payload acceptance in explicit decryption in MongoDB libmongocrypt

The explicit decryption component of MongoDB libmongocrypt can return an unrecognized encrypted payload unchanged instead of returning a decryption error. An actor who can modify stored encrypted fields, such as a database writer, server, or network intermediary, can cause an affected application to process the supplied bytes as decrypted plaintext.

CVE-2026-106433 High · 8.8 CWE-843 Oct 8, 2026

Heap corruption via duplicate masterKey fields in MongoDB libmongocrypt

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.

CVE-2026-106429 Medium · 6.5 CWE-191 Oct 8, 2026

Application denial of service via malformed KMS endpoint in MongoDB libmongocrypt

An integer underflow in the KMS endpoint-parsing logic of MongoDB libmongocrypt can cause an allocation failure that terminates the application process. This can occur when an authenticated user modifies a key document in the key vault collection, or when an application accepts a KMS endpoint containing a colon after its path or query during key creation. The issue does not access memory outside its allocated bounds.

CVE-2026-84962 Medium · 4.2 CWE-93 Sep 3, 2026

Authenticated KMS request forgery via CRLF injection in GCP key identifier strings

An unauthorized user with key vault write access may cause an authorized client to issue arbitrary authenticated Google Cloud KMS API calls under the authorized user's identity, escalating database-level access into cloud key control and defeating client-side encryption.

CVE-2026-84971 Medium · 6.5 CWE-617 Sep 3, 2026

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

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.

CVE-2026-81523 Medium · 4.4 CWE-74 Aug 27, 2026

Cross-tenant database retargeting via dot/NUL injection in namespace strings in libmongocrypt

A missing input-validation issue in MongoDB libmongocrypt's automatic-encryption context setup allows a caller-supplied database identifier to be accepted without sanitization. The resulting impact is limited to incorrect schema selection, which may lead to limited disclosure or modification of information handled by the application.