# CVE-2026-84968: MongoDB PHP Driver out-of-bounds read in BSON decoding

Source: https://junglewise.ai/threats/cve-2026-84968-mongodb-php-driver-out-of-bounds-read-in-bson-decoding  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-09-03. Updated: 2026-09-25  
License: CC BY 4.0 with a link back

CVE-2026-84968 · Severity: medium · CVSS 5.3 · Published 2026-09-03

The MongoDB PHP driver contains a flaw in how it processes corrupted data format (BSON). When an application receives specially crafted input, the driver may read memory beyond its intended bounds and leak that data in error messages sent back to the application, potentially exposing sensitive information from the server's memory.

Technologies: [MongoDB PHP Driver](https://junglewise.ai/threats/technologies/php-driver). Vendors: [MongoDB](https://junglewise.ai/threats/vendors/mongodb).

## Quick answers

**Is CVE-2026-84968 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-84968 being exploited in the wild.

**How severe is CVE-2026-84968?** Medium severity, with a CVSS score of 5.3, published 3 September 2026.

**Which products and versions are affected?** MongoDB PHP Driver before 1.21.9, before 2.1.9, before 2.5.2.

**Is there a fix for CVE-2026-84968?** A patch was published on 2026-09-03: Fixed in versions 1.21.9, 2.1.9, and 2.5.2 Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-84968 attacked?** It is attacked over the network, in a software library.

**Am I affected by CVE-2026-84968?** Check whether you run MongoDB PHP Driver at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## Technical details

An out-of-bounds read vulnerability exists in the BSON decoding component of the MongoDB PHP driver. The vulnerability is triggered when the driver processes malformed BSON input without proper bounds checking. An unauthenticated attacker can supply specially crafted BSON data to cause an out-of-bounds memory read, with adjacent process memory contents copied into error messages returned to application code. This allows limited disclosure of unintended memory contents. The vulnerability has been fixed in versions 2.5.2, 1.21.9, and 2.1.9.

## Affected products

- MongoDB PHP Driver before 1.21.9, before 2.1.9, before 2.5.2

## Timeline

- 2026-09-03: disclosed
- 2026-09-03: patched: Fixed in versions 1.21.9, 2.1.9, and 2.5.2

## References

- [https://jira.mongodb.org/browse/PHPC-2744](https://jira.mongodb.org/browse/PHPC-2744)

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