What’s Vulnerable › Vulnerabilities

CVE-2026-81525: Cross-tenant database retargeting via dot/NUL injection in namespace strings in the PHP Driver

• Severity: high (CVSS 8.1 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.5% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-08-27 · updated 2026-09-29
• Weakness: CWE-943

Description

The MongoDB client library for PHP does not sufficiently sanitize special elements in application-supplied namespace identifiers before using them to construct the target namespace for database operations. An application that incorporates untrusted text into these identifiers may have operations silently directed at a different storage location than the one the application intended.

Affected products

• MongoDB PHP Driver: before 1.21.6; from 2.0.0 before 2.4.1 — fixed in 1.21.6, 2.4.1
• MongoDB PHP Library: before 1.21.4; from 2.0.0 before 2.4.1 — fixed in 1.21.4, 2.4.1

How to fix

Upgrade to a fixed version: MongoDB PHP Driver 1.21.6, 2.4.1; MongoDB PHP Library 1.21.4, 2.4.1. Check the vendor advisory for mitigations.

References

• https://github.com/mongodb/mongo-php-driver/releases/tag/1.21.6
• https://github.com/mongodb/mongo-php-driver/releases/tag/2.4.1
• https://github.com/mongodb/mongo-php-library/releases/tag/1.21.4
• https://github.com/mongodb/mongo-php-library/releases/tag/2.4.1
• https://jira.mongodb.org/browse/PHPLIB-1927

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