CVE-2026-82054: MongoDB Server JSON Parser DOS Vulnerability

CVE-2026-82054 Overview

CVE-2026-82054 is a resource exhaustion vulnerability in the MongoDB server's JSON Pointer parser. The flaw exists in the code path that handles $jsonSchema query filter processing during find commands. An authenticated attacker can submit a specially crafted $jsonSchema filter that triggers significant memory amplification during parsing. The parser does not enforce adequate limits on iteration count or total allocation size. Under concurrent request load, cumulative memory consumption can exhaust heap memory. The operating system's out-of-memory handler then terminates the mongod process, denying service to all connected clients. The weakness is categorized under [CWE-770: Allocation of Resources Without Limits or Throttling].

Critical Impact
A low-privileged authenticated user can crash the mongod process remotely by sending crafted find commands, terminating database service for all connected clients.

Affected Products

MongoDB Server (versions affected by SERVER-130901)
Deployments exposing the find command with $jsonSchema filter support
Any MongoDB instance accepting authenticated queries from untrusted or shared tenants

Discovery Timeline

2026-09-08 - CVE-2026-82054 published to the National Vulnerability Database (NVD)
2026-09-08 - Last updated in NVD database

Technical Details for CVE-2026-82054

Vulnerability Analysis

The vulnerability resides in MongoDB's JSON Pointer parser, which is invoked when the server evaluates $jsonSchema filter expressions inside a find command. When a client submits a query containing a crafted $jsonSchema filter, the parser iterates over structures in the input without capping iteration counts or bounding the cumulative memory it allocates. A single request can therefore expand into a much larger in-memory representation than the input size suggests. When multiple such requests arrive concurrently, allocations accumulate across worker threads. Heap memory is exhausted, the Linux OOM killer terminates mongod, and every connected session is dropped. Recovery requires process restart, and repeated attacks can be used to keep the database unavailable.

Root Cause

The root cause is missing input validation on parser workload. The JSON Pointer parser does not enforce ceilings on iteration count or total allocation size while processing $jsonSchema content. This maps to [CWE-770], where a resource is allocated proportionally to attacker-controlled input without a throttle.

Attack Vector

Exploitation requires network access to the MongoDB service and low-privilege authenticated credentials sufficient to issue a find command. The attacker sends one or more find commands whose filter includes a crafted $jsonSchema expression. Concurrency amplifies the impact: multiple parallel requests drive the process past its memory budget. The scope is limited to availability; the flaw does not disclose or modify data.

No verified public exploit code is available. See the MongoDB Jira Issue SERVER-130901 for the vendor's technical description.

Detection Methods for CVE-2026-82054

Indicators of Compromise

Unexpected termination of the mongod process with Linux OOM killer entries in dmesg or /var/log/messages referencing mongod.
Sudden mass client disconnects correlated with spikes in resident memory usage on the database host.
MongoDB audit or profiler entries showing find commands with large or deeply nested $jsonSchema filter fields from a single principal.

Detection Strategies

Enable MongoDB command auditing and alert on find operations that reference $jsonSchema with abnormally large payload sizes.
Correlate mongod process restarts with preceding query telemetry to identify the client, source IP, and authenticated user that issued the triggering requests.
Baseline normal memory consumption of mongod and alert when working set growth deviates sharply within short intervals.

Monitoring Recommendations

Ship mongod logs, system journal, and OOM killer events into a centralized analytics platform for correlation.
Track per-client query rate and payload size for accounts permitted to submit $jsonSchema filters.
Monitor host-level memory pressure metrics (RSS, page faults, swap usage) on database nodes and alert on rapid ramps.

How to Mitigate CVE-2026-82054

Immediate Actions Required

Apply the MongoDB patch referenced in SERVER-130901 as soon as it is available for your release branch.
Restrict database roles so that only trusted service accounts can issue find commands with $jsonSchema filters against production collections.
Rotate or revoke credentials for any low-privileged accounts exposed to untrusted networks until patching is complete.

Patch Information

MongoDB tracks the fix under the internal ticket SERVER-130901. Consult the vendor advisory and the release notes for your MongoDB major version to identify the specific patched build, then upgrade all replica set members and mongos routers to that build.

Workarounds

Place mongod behind a query proxy or application layer that rejects find filters containing $jsonSchema when not required by the workload.
Enforce per-connection request rate limits and maximum command size limits at the network or driver layer to blunt concurrent amplification.
Configure the database host with cgroup memory limits and process supervisors so that OOM events restart mongod quickly and are alerted on.
Remove find privileges from accounts that do not require ad-hoc query capability, reducing the attack surface for CVE-2026-82054.

bash

# Example: restrict $jsonSchema usage by revoking find on sensitive collections
# Run in the mongo shell as an administrator
use admin
db.revokeRolesFromUser(
  "reporting_user",
  [ { role: "read", db: "production" } ]
)

# Example systemd override to bound mongod memory and auto-restart on OOM
# /etc/systemd/system/mongod.service.d/override.conf
[Service]
MemoryMax=8G
Restart=always
RestartSec=5s