What’s Vulnerable › Vulnerabilities

CVE-2026-81522: Cross-tenant database retargeting via dot/NUL injection in namespace strings in the C++ 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-116

Description

A weakness in the MongoDB C++ Driver's handling of caller-supplied namespace identifiers allows special characters embedded in those identifiers. An application that builds a namespace identifier from untrusted input without validating it may therefore have its operation directed at a different target than intended. This can result in limited unauthorized read and write access to data belonging to another logical tenant of the affected application.

Affected products

• MongoDB C++ Driver: from 3.0.0 before 4.5.2 — fixed in 4.5.2

How to fix

Upgrade to a fixed version: MongoDB C++ Driver 4.5.2. Check the vendor advisory for mitigations.

References

• https://github.com/mongodb/mongo-cxx-driver/releases/tag/r4.5.1
• https://jira.mongodb.org/browse/CXX-3552

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