Vulnerability · Published Aug 27, 2026 · Assigned by mongodb
CVE-2026-81523Cross-tenant database retargeting via dot/NUL injection in namespace strings in libmongocrypt
Medium 4.4
In plain English
A medium-severity injection in libmongocrypt from MongoDB. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.1% (higher than 1% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Official description
A missing input-validation issue in MongoDB libmongocrypt's automatic-encryption context setup allows a caller-supplied database identifier to be accepted without sanitization. The resulting impact is limited to incorrect schema selection, which may lead to limited disclosure or modification of information handled by the application.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian:12 | libmongocrypt | no fix listed | DEBIAN-CVE-2026-81523 |
| Debian:13 | libmongocrypt | 1.13.2-1+deb13u1 | DEBIAN-CVE-2026-81523 |
| Debian:14 | libmongocrypt | 1.20.3-1 | DEBIAN-CVE-2026-81523 |
| Ubuntu:22.04:LTS | libmongocrypt | no fix listed | UBUNTU-CVE-2026-81523 |
| Ubuntu:24.04:LTS | libmongocrypt | no fix listed | UBUNTU-CVE-2026-81523 |
| Ubuntu:26.04:LTS | libmongocrypt | no fix listed | UBUNTU-CVE-2026-81523 |
| Ubuntu:26.10 | libmongocrypt | no fix listed | UBUNTU-CVE-2026-81523 |
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| MongoDB | libmongocrypt | 1.0.0 – before 1.20.3 |
Weakness: CWE-74 · Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N