Severity by source
CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:N/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
Primary rating from Vendor (mongodb) · only source for this CVE.
CVSS VectorVendor: mongodb
CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:N/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
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6DescriptionCVE.org
The $_internalApplyOplogUpdate aggregation pipeline stage can be used to execute a document diff containing a malformed binary diff to return memory out-of-bounds or crash the server. $_internalApplyOplogUpdate can be executed by any authenticated user with access to the aggregate command.
AnalysisAI
Memory disclosure and denial-of-service in MongoDB Server allows any authenticated user with aggregate command privileges to crash the database or read out-of-bounds memory by submitting a malformed binary diff through the $_internalApplyOplogUpdate aggregation pipeline stage. The flaw stems from inadequate validation of the binary diff document structure consumed by an internal oplog replay operator that is unexpectedly reachable from user-facing aggregation queries. No public exploit identified at time of analysis, but the low privilege bar and network attack vector make this a meaningful threat in multi-tenant or shared-credential MongoDB deployments.
Technical ContextAI
MongoDB's $_internalApplyOplogUpdate is an internal aggregation pipeline stage normally used by the replication subsystem to apply oplog (operations log) entries containing compact binary deltas describing document mutations. The vulnerability falls under CWE-1287 (Improper Validation of Specified Type of Input): the stage trusts the structural integrity of the binary diff payload supplied by the caller, and a malformed diff causes the parser to read past allocated buffer bounds, producing either an information-leaking response or a fatal mongod process crash. The CPE cpe:2.3:a:mongodb:mongodb_server:*:*:*:*:*:*:*:* indicates the MongoDB Server product is affected across versions, though the upstream tracker (SERVER-124959) is the authoritative source for exact builds.
RemediationAI
No vendor-released patch identified at time of analysis from the provided data; consult https://jira.mongodb.org/browse/SERVER-124959 for the fix release once MongoDB publishes a patched server build and upgrade to that exact version when available. Until a patched build can be deployed, the most effective compensating control is to revoke aggregate-command privileges from any role that does not strictly require it and audit built-in roles such as read, readWrite, and any custom roles for the find privilege on collections - the trade-off is that legitimate analytics, reporting, and ORM-driven aggregation queries will break for affected principals. Additionally, restrict network reachability of mongod (default 27017) to known application subnets via firewall or bindIp configuration to ensure the PR:L prerequisite cannot be satisfied by opportunistic external attackers who obtain leaked credentials. Monitor mongod logs for unexpected aggregation pipelines referencing $_internalApplyOplogUpdate, since this internal stage should not appear in normal application traffic.
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External POC / Exploit Code
Leaving vuln.today
EUVD-2026-35852
GHSA-j72p-fv5p-4r63