CVE-2026-81522 Cross-tenant database retargeting via dot/NUL injection in namespace strings in the C++ Driver
Attackers can redirect database operations to other tenants via namespace injection, causing unauthorized data access and modification in applications using the MongoDB C++ Driver.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-81522?
CVE-2026-81522 is a high-severity vulnerability in MongoDB C++ Driver, published on 27 Aug 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Official 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.
Weakness: CWE-116
Which versions are affected by CVE-2026-81522?
It affects 1 product.
Products include Mongodb C\+\+ Driver.
How do I fix CVE-2026-81522?
Apply the vendor's patch.
Is CVE-2026-81522 being exploited?
There is no known exploitation of CVE-2026-81522 in the wild and no public exploit code.
Other vulnerabilities in MongoDB C++ Driver
- CVE-2026-88034 GridFS data disclosure and deletion via query-operator injection in file IDs in the MongoDB C++ Driver
- CVE-2026-84966 BSON element injection via NUL-embedded document keys in builder append
- CVE-2026-84970 Heap over-read or silent misparse via 32-bit truncation of JSON length in BSON JSON parser
Sources
Also known as DEBIAN-CVE-2026-81522, UBUNTU-CVE-2026-81522.