CVE-2026-89099: 
MongoDB vulnerability analysis and mitigation

CVE-2026-89099 is a race condition vulnerability in the document value layer of MongoDB Server that allows concurrent server threads to operate on the same internal memory without synchronization, leading to memory corruption. An authenticated user with ordinary read-write database privileges can trigger this condition over the normal client protocol, resulting in server termination and potential corruption of process memory with user-influenced content. The vulnerability affects MongoDB Server versions 7.0.0–7.0.42, 8.0.0–8.0.31, and 8.3.0–8.3.10, with fixed versions available. It carries a CVSS v3.1 score of 7.5 (High) and a CVSS v4.0 score of 7.7 (High) (GitHub Advisory, Feedly).

The root cause is classified as CWE-362 (Concurrent Execution using Shared Resource with Improper Synchronization / Race Condition). In MongoDB Server's document value layer, concurrent server threads can access and modify the same internal memory region without proper locking or synchronization primitives, creating a timing window for exploitation. An authenticated attacker with read-write privileges can craft database operations sent over the standard MongoDB client protocol to trigger this race condition, causing memory corruption with attacker-influenced content. The attack requires specific timing conditions (Attack Requirements: Present in CVSS v4.0), making reliable exploitation non-trivial (GitHub Advisory, MongoDB JIRA).

Successful exploitation can impact the confidentiality, integrity, and availability of the affected MongoDB server process. The race condition can cause server termination (denial of service) and corruption of process memory with user-influenced content, potentially enabling an attacker to influence server behavior or expose sensitive in-memory data. The scope is limited to the vulnerable server process itself, with no direct subsequent system impact indicated, but database unavailability and data integrity risks are significant for dependent applications (GitHub Advisory, Feedly).

There is no known public proof-of-concept exploit and no evidence of in-the-wild exploitation at the time of disclosure (Feedly). The EPSS score is 0.0, reflecting a very low current probability of exploitation. The vulnerability is not listed in the CISA Known Exploited Vulnerabilities (KEV) catalog. Exploitation is not automatable due to the timing-dependent nature of the race condition, and requires authenticated access with read-write database privileges, limiting the attacker pool.

• Logs: Unexpected MongoDB server crash logs or abnormal process termination entries in mongod.log; error messages referencing memory access violations or segmentation faults.
• Process: MongoDB server process (mongod) restarting unexpectedly or exiting with non-zero exit codes; unusual memory usage spikes preceding crashes.
• Network: Repeated or unusual database write operations from a single authenticated client, particularly those that appear to be timing-sensitive or concurrent in nature.

MongoDB has released patched versions addressing this vulnerability: upgrade to MongoDB Server 7.0.43 or later (for 7.0.x users), 8.0.32 or later (for 8.0.x users), or 8.3.11 or later (for 8.3.x users) (GitHub Advisory, MongoDB JIRA). As interim mitigations, restrict database read-write privileges to only trusted users and applications, implement network segmentation to limit which hosts can connect to MongoDB instances, and monitor server logs for unexpected crashes or memory corruption indicators.