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PatchSiren cyber security CVE debrief

CVE-2026-6811 MongoDB Inc. CVE debrief

A stack exhaustion vulnerability in the MongoDB PHP driver can cause application crashes when processing deeply nested BSON documents in unusual circumstances. This issue arises when the source of these BSON documents is not MongoDB Server. The vulnerability has a CVSS score of 6 and is classified as MEDIUM severity. The affected versions are between 1.21.0 and 1.21.5 and between 2.1.0 and 2.1.8. Defenders and developers using the MongoDB PHP driver, especially those who process BSON documents from untrusted sources, should assess their exposure and take necessary actions to verify the versions in use and update if necessary.

Vendor
MongoDB Inc.
Product
PHP Driver
CVSS
MEDIUM 6
CISA KEV
Not listed in stored evidence
Original CVE published
2026-05-14
Original CVE updated
2026-09-24
Advisory published
2026-05-14
Advisory updated
2026-09-24

Who should care

Defenders and developers using the MongoDB PHP driver, especially those who process BSON documents from untrusted sources, should assess their exposure and take necessary actions.

Why it matters

Defenders should care about CVE-2026-6811 because it can cause application crashes, potentially leading to denial-of-service attacks, and requires verification of the MongoDB PHP driver versions in use.

  • Application crashes due to stack exhaustion
  • Potential denial-of-service (DoS) attacks
  • Need for version verification and updates

Technical summary

The vulnerability is caused by a stack exhaustion issue in the MongoDB PHP driver when processing deeply nested BSON documents in unusual circumstances. The affected versions are between 1.21.0 and 1.21.5 and between 2.1.0 and 2.1.8. This issue arises when the source of these BSON documents is not MongoDB Server. Defenders should prioritize verifying the versions of the MongoDB PHP driver in use and assess the potential impact on their systems.

Defensive priority

Defenders should prioritize verifying the versions of the MongoDB PHP driver in use, especially versions between 1.21.0 and 1.21.5 and between 2.1.0 and 2.1.8, and assess the potential impact on their systems.

Recommended defensive actions

  • Verify the version of the MongoDB PHP driver in use and assess potential impact
  • Review and update the driver to a version outside the vulnerable range if necessary
  • Monitor for unusual BSON document processing activity

Evidence notes

The CVE record and NVD vulnerability detail provide information on the vulnerability, including its description, CVSS score, and affected versions. The vulnerability is caused by a stack exhaustion issue in the MongoDB PHP driver when processing deeply nested BSON documents in unusual circumstances. Evidence is based on CVE Program and NVD sources. Defenders should verify the MongoDB PHP driver versions in use, especially versions between 1.21.0 and 1.21.5 and between 2.1.0 and 2.1.8,

Sources and references

Verified primary and authoritative sources

  • CVE-2026-6811 CVE Program record

    Publisher, destination, and source semantics verified

    URL: https://www.cve.org/CVERecord?id=CVE-2026-6811

    CVE Program - Official CVE Program record with source-provided CVE metadata.

  • CVE-2026-6811 NVD vulnerability detail

    Publisher, destination, and source semantics verified

    URL: https://nvd.nist.gov/vuln/detail/CVE-2026-6811

    NIST National Vulnerability Database - Official NIST NVD detail page and source-specific vulnerability assessment.

Supplemental references

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.