CVE-2017-8820

Publication date 3 December 2017

Last updated 25 August 2025

Ubuntu priority

Cvss 3 Severity Score

Description

In Tor before 0.2.5.16, 0.2.6 through 0.2.8 before 0.2.8.17, 0.2.9 before 0.2.9.14, 0.3.0 before 0.3.0.13, and 0.3.1 before 0.3.1.9, remote attackers can cause a denial of service (NULL pointer dereference and application crash) against directory authorities via a malformed descriptor, aka TROVE-2017-010.

From the Ubuntu Security Team

ebarretto> The problematic code was introduced in 0.2.9.4-alpha

Status

Show unmaintained releases

Package	Ubuntu Release	Status
tor	18.10 cosmic	Not affected
	18.04 LTS bionic	Not affected
	17.10 artful	Fixed 0.3.0.13-0ubuntu1~17.10.2
	17.04 zesty	Ignored end of life
	16.04 LTS xenial	Fixed 0.2.9.14-1ubuntu1~16.04.2
	14.04 LTS trusty	Not affected

Severity score breakdown

Parameter	Value
Base score	7.5 · High
Attack vector	Network
Attack complexity	Low
Privileges required	None
User interaction	None
Scope	Unchanged
Confidentiality	None
Integrity impact	None
Availability impact	High
Vector	CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H