Vulnerability · Published Aug 27, 2026 · Assigned by mongodb
CVE-2026-81521Cross-database write retargeting via unvalidated dotted database name in Client.BulkWrite in the MongoDB Go Driver
Medium 6.5
In plain English
A medium-severity security flaw in GO Driver from MongoDB. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.2% (higher than 15% of all known vulnerabilities).
Official description
The MongoDB Go Driver's client-level bulk write operation may accept a caller-supplied database name containing a reserved separator character without escaping it before the name is used to build the target namespace for the operation. An application that passes untrusted input as a database name could therefore have the write directed at a database and collection other than the ones it intended. Only the Client.BulkWrite API is affected.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian:12 | golang-mongodb-mongo-driver | no fix listed | DEBIAN-CVE-2026-81521 |
| Debian:13 | golang-mongodb-mongo-driver | no fix listed | DEBIAN-CVE-2026-81521 |
| Debian:14 | golang-mongodb-mongo-driver | no fix listed | DEBIAN-CVE-2026-81521 |
| Ubuntu:24.04:LTS | golang-mongodb-mongo-driver | no fix listed | UBUNTU-CVE-2026-81521 |
| Ubuntu:26.04:LTS | golang-mongodb-mongo-driver | no fix listed | UBUNTU-CVE-2026-81521 |
| Ubuntu:26.10 | golang-mongodb-mongo-driver | no fix listed | UBUNTU-CVE-2026-81521 |
Affected products (as reported)
Weakness: CWE-99 · Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N