Vulnerability · Published Oct 8, 2026 · Assigned by mongodb
CVE-2026-106433Heap corruption via duplicate masterKey fields in MongoDB libmongocrypt
High 8.8
In plain English
A high-severity type confusion 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 0.3% (higher than 18% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Official description
Improper state management in MongoDB libmongocrypt can cause provider-specific data to be treated as an incompatible type when cleaning up a key document containing duplicate masterKey fields. An authenticated actor who can modify key vault documents, or a server that returns such a key document, can cause invalid memory access and invalid frees in the client process. This can terminate the application or corrupt process memory.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian:12 | libmongocrypt | no fix listed | DEBIAN-CVE-2026-106433 |
| Debian:13 | libmongocrypt | no fix listed | DEBIAN-CVE-2026-106433 |
| Debian:14 | libmongocrypt | 1.20.5-1 | DEBIAN-CVE-2026-106433 |
| Ubuntu:22.04:LTS | libmongocrypt | no fix listed | UBUNTU-CVE-2026-106433 |
| Ubuntu:24.04:LTS | libmongocrypt | no fix listed | UBUNTU-CVE-2026-106433 |
| Ubuntu:26.04:LTS | libmongocrypt | no fix listed | UBUNTU-CVE-2026-106433 |
| Ubuntu:26.10 | libmongocrypt | no fix listed | UBUNTU-CVE-2026-106433 |
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| MongoDB | libmongocrypt | 1.1.0 – before 1.20.5 |
Weakness: CWE-843 · Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H