CVE-2026-6811Network attack vector

Application crash via unchecked BSON nesting

Published May 14, 2026 · Updated May 14, 2026

Uncontrolled recursion in MongoDB PHP Driver 1.21.5 and 2.1.8 allows attackers to crash PHP applications via deeply nested BSON. The BSON encoder recursively traverses PHP arrays and objects without enforcing libbson's 100-level nesting limit, exhausting the process stack. Reachability requires an application to encode deeply nested, attacker-influenced data that did not originate from MongoDB Server; the bounded result is a PHP application crash.

CVSS severity6.0
Medium
EPSS probability0.35%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Uncontrolled recursion in MongoDB PHP Driver 1.21.5 and 2.1.8 allows attackers to crash PHP applications via deeply nested BSON. The BSON encoder recursively traverses PHP arrays and objects without enforcing libbson's 100-level nesting limit, exhausting the process stack. Reachability requires an application to encode deeply nested, attacker-influenced data that did not originate from MongoDB Server; the bounded result is a PHP application crash.

The record

CVE
CVE-2026-6811
Published
May 14, 2026
Updated
May 14, 2026
Vendor
MongoDB
Product
MongoDB PHP Driver
Classifications
CWE-674, CAPEC-230, T1499.004
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. May 14, 2026CVE publishedPublication date reported by the CVE source.
  2. May 14, 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=1.21.5
  2. Affected versionversion=2.1.8

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

MongoDB · MongoDB PHP Driverversion=1.21.5; version=2.1.8

Published CVSS scores

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

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
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-674Uncontrolled Recursion
CAPEC-230Serialized Data with Nested Payloads
T1499.004Endpoint Denial of Service: Application or System Exploitation

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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