Vulnerability · Published Oct 8, 2026 · Assigned by mongodb
CVE-2026-106434Unrecognized payload acceptance in explicit decryption in MongoDB libmongocrypt
Medium 4.3
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 0.1% (higher than 1% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Official description
The explicit decryption component of MongoDB libmongocrypt can return an unrecognized encrypted payload unchanged instead of returning a decryption error. An actor who can modify stored encrypted fields, such as a database writer, server, or network intermediary, can cause an affected application to process the supplied bytes as decrypted plaintext.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian:12 | libmongocrypt | no fix listed | DEBIAN-CVE-2026-106434 |
| Debian:13 | libmongocrypt | no fix listed | DEBIAN-CVE-2026-106434 |
| Debian:14 | libmongocrypt | 1.20.5-1 | DEBIAN-CVE-2026-106434 |
| Ubuntu:22.04:LTS | libmongocrypt | no fix listed | UBUNTU-CVE-2026-106434 |
| Ubuntu:24.04:LTS | libmongocrypt | no fix listed | UBUNTU-CVE-2026-106434 |
| Ubuntu:26.04:LTS | libmongocrypt | no fix listed | UBUNTU-CVE-2026-106434 |
| Ubuntu:26.10 | libmongocrypt | no fix listed | UBUNTU-CVE-2026-106434 |
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| MongoDB | libmongocrypt | 1.5.0 – before 1.20.5 |
Weakness: CWE-354 · Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N