Description

A race condition in the document value layer of MongoDB Server can allow concurrent server threads to operate on the same internal memory without synchronization, leading to memory corruption. An authenticated user holding ordinary read-write privileges on a database may be able to trigger this condition over the normal client protocol, resulting in server termination and potential corruption of process memory with user-influenced content. Successful use of this issue may impact the confidentiality, integrity, and availability of the affected server process.

Executive Summary

Technical Details

Mitigations

References

Additional Metadata

{
  "score": "7.5",
  "pubDate": "2026-09-11T18:17:00.360Z",
  "pubdate": "2026-09-11T18:17:00.360Z",
  "executiveSummary": "A critical race condition vulnerability exists within the document value layer of MongoDB Server, originating from improper synchronization of concurrent threads accessing shared internal memory.\nThe vulnerability allows an authenticated user with standard read-write database privileges to trigger memory corruption via the standard client protocol.\nExploitation leads to immediate server process termination (Denial of Service) and provides a vector for potential memory corruption, which may result in unauthorized data exposure or manipulation.\nThis issue impacts the confidentiality, integrity, and availability of the database system, as attackers can influence the state of the process memory.\nSuccessful exploitation requires an established authenticated session with sufficient privileges to interact with the database, representing a significant risk to internal server stability and data security.",
  "technicalDetails": "The root cause of this vulnerability is a lack of thread synchronization primitives within the document value layer of the MongoDB Server architecture.\nWhen concurrent server threads attempt to access or mutate the same internal memory region simultaneously, a race condition occurs, bypassing the intended concurrency control mechanisms.\nThe exploitation flow begins when an authenticated user sends specifically crafted operations over the client protocol to the targeted database.\nBy orchestrating concurrent read/write requests, the attacker induces a state where the server logic concurrently operates on memory addresses without appropriate locking or atomic operations.\nThis improper access leads to a data race where one thread may modify a document value while another thread is performing operations on that same memory address, causing memory corruption.\nBecause the attacker has read-write privileges, they can influence the content within these memory locations, potentially leading to arbitrary data being written to internal structures or the corruption of pointers within the process memory space.\nThe final outcome of this corruption often results in a segmentation fault or an assertion failure, causing the immediate termination of the MongoDB Server process (Denial of Service).\nFurthermore, the ability to introduce user-influenced content into these corrupted memory regions potentially permits the escalation of the vulnerability beyond a simple crash, endangering the integrity of the data handled by the process and the confidentiality of memory-resident information.\nThe vulnerability is situated within the document value layer of the MongoDB engine and persists until the affected code paths are patched to include proper mutexes, read-write locks, or atomic memory operations to ensure thread safety during data retrieval and mutation operations."
}