Vulnerability · Published Oct 8, 2026 · Assigned by mongodb
CVE-2026-106429Application denial of service via malformed KMS endpoint in MongoDB libmongocrypt
Medium 6.5
In plain English
A medium-severity security flaw 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 22% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Official description
An integer underflow in the KMS endpoint-parsing logic of MongoDB libmongocrypt can cause an allocation failure that terminates the application process. This can occur when an authenticated user modifies a key document in the key vault collection, or when an application accepts a KMS endpoint containing a colon after its path or query during key creation. The issue does not access memory outside its allocated bounds.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian:12 | libmongocrypt | no fix listed | DEBIAN-CVE-2026-106429 |
| Debian:13 | libmongocrypt | no fix listed | DEBIAN-CVE-2026-106429 |
| Debian:14 | libmongocrypt | 1.20.5-1 | DEBIAN-CVE-2026-106429 |
| Ubuntu:22.04:LTS | libmongocrypt | no fix listed | UBUNTU-CVE-2026-106429 |
| Ubuntu:24.04:LTS | libmongocrypt | no fix listed | UBUNTU-CVE-2026-106429 |
| Ubuntu:26.04:LTS | libmongocrypt | no fix listed | UBUNTU-CVE-2026-106429 |
| Ubuntu:26.10 | libmongocrypt | no fix listed | UBUNTU-CVE-2026-106429 |
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| MongoDB | libmongocrypt | 1.1.0 – before 1.20.5 |
Weakness: CWE-191 · Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H