CVE-2021-3716

Publication date 2 March 2022

Last updated 11 July 2025

Ubuntu priority

Cvss 3 Severity Score

Description

A flaw was found in nbdkit due to to improperly caching plaintext state across the STARTTLS encryption boundary. A MitM attacker could use this flaw to inject a plaintext NBD_OPT_STRUCTURED_REPLY before proxying everything else a client sends to the server, potentially leading the client to terminate the NBD session. The highest threat from this vulnerability is to system availability.

Read the notes from the security team

Status

Show unmaintained releases

Package	Ubuntu Release	Status
nbdkit	25.10 questing	Needs evaluation
	25.04 plucky	Needs evaluation
	24.10 oracular	Ignored end of life, was needs-triage
	24.04 LTS noble	Needs evaluation
	23.10 mantic	Ignored end of life, was needs-triage
	23.04 lunar	Ignored end of life, was needs-triage
	22.10 kinetic	Ignored end of life, was needs-triage
	22.04 LTS jammy	Needs evaluation
	21.10 impish	Ignored end of life
	21.04 hirsute	Ignored end of life
	20.04 LTS focal	Needs evaluation
	18.04 LTS bionic	Not in release
	16.04 LTS xenial	Needs evaluation
	14.04 LTS trusty	Not in release

Notes

sbeattie

introduced in eaa4c6e9a (v1.11.8)

Severity score breakdown

Parameter	Value
Base score	3.1 · Low
Attack vector	Network
Attack complexity	High
Privileges required	Low
User interaction	None
Scope	Unchanged
Confidentiality	None
Integrity impact	None
Availability impact	Low
Vector	CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:L