CVE-2026-84968

An uncontrolled recursion weakness in the BSON decoding logic of the MongoDB PHP driver may allow an unauthenticated party who can supply crafted binary document data to the decoder to exhaust the process stack. This may cause the PHP process using the driver to terminate unexpectedly, resulting in a loss of availability for that process.

The BSON encoder in the MongoDB PHP Driver does not check some return values after a document exceeds libbson's size limit. This can leave the encoder in an invalid state. An unauthenticated actor who can cause an affected application to encode an unusually large data structure can terminate the PHP worker or cause the resulting document to omit fields. No MongoDB server connection or database authentication is required.

The BSON encoder in the MongoDB PHP Driver converts a string length to a 32-bit value without validation. For strings near 4 GiB, allocation can wrap while copy uses original length, causing heap buffer overflow. Requires non-default runtime configuration allowing multi-gigabyte values.

A deserialization vulnerability in the command monitoring support of the MongoDB PHP Driver can cause class names from document content to be honored when building monitoring events. An attacker controlling data in database operations may instantiate application classes implementing the persistable interface and invoke their unserialize method.

A stack exhaustion vulnerability in the MongoDB PHP driver can cause application crashes when processing deeply nested BSON documents in unusual circumstances when the source of these BSON documents is not MongoDB Server.