CVE-2021-20330

Publication date 15 December 2021

Last updated 18 February 2026

Ubuntu priority

Cvss 3 Severity Score

Description

An attacker with basic CRUD permissions on a replicated collection can run the applyOps command with specially malformed oplog entries, resulting in a potential denial of service on secondaries. This issue affects MongoDB Server v4.0 versions prior to 4.0.27; MongoDB Server v4.2 versions prior to 4.2.16; MongoDB Server v4.4 versions prior to 4.4.9.

Read the notes from the security team

Status

Show unmaintained releases

Package	Ubuntu Release	Status
mongodb	20.04 LTS focal	Not affected
	18.04 LTS bionic	Not affected
	16.04 LTS xenial	Not affected
	14.04 LTS trusty	Not affected

Notes

john-breton

Patches were released after the switch to SSPL upstream, as such we cannot use them to patch Ubuntu releases. The hope is a license-compliant third-party will make patches available in the future.

Patch details

For informational purposes only. We recommend not to cherry-pick updates. How can I get the fixes?

Package	Patch details
mongodb	Upstream: cbec187 Upstream: 865ecca Upstream: 7e053b6

Severity score breakdown

CVSS version: CVSS v3.0

Base score 6.5 · Medium

Base metrics

Parameter	Value
Attack vector	Network
Attack complexity	Low
Privileges required	Low
User interaction	None
Scope	Unchanged
Confidentiality impact	None
Integrity impact	None
Availability impact	High

Scores

Parameter	Value
Base score	6.5 · Medium
Exploitability score	-
Impact score	-

Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H