CVE-2026-9100Network attack vector

Memory disclosure and crash via malformed GridFS metadata

Published May 20, 2026 · Updated May 20, 2026

GridFS metadata validation flaws in MongoDB C Driver allow remote authenticated users to read process memory or crash applications. _mongoc_gridfs_file_new_from_bson accepts a zero chunkSize, while the page reader subtracts an offset beyond the actual chunk length. Exploitation requires write access to craft GridFS metadata and an application read through the legacy API; outcomes are memory disclosure or process termination.

CVSS severity6.0
Medium
EPSS probability0.29%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

GridFS metadata validation flaws in MongoDB C Driver allow remote authenticated users to read process memory or crash applications. _mongoc_gridfs_file_new_from_bson accepts a zero chunkSize, while the page reader subtracts an offset beyond the actual chunk length. Exploitation requires write access to craft GridFS metadata and an application read through the legacy API; outcomes are memory disclosure or process termination.

The record

CVE
CVE-2026-9100
Published
May 20, 2026
Updated
May 20, 2026
Vendor
MongoDB
Product
MongoDB C++ Driver
Classifications
CWE-1285
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. May 20, 2026CVE publishedPublication date reported by the CVE source.
  2. May 20, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=1.0 <1.30.8
  2. Affected versionversion=2.0 <2.2.4

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

MongoDB · MongoDB C++ Driverversion=1.0 <1.30.8; version=2.0 <2.2.4

Published CVSS scores

6.0MongoDB, Inc.CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:L/VI:N/VA:H/SC:N/SI:N/SA:N
5.9MongoDB, Inc.CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:L/I:N/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-1285Improper Validation of Specified Index, Position, or Offset in Input

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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