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

CVSS version: CVSS v3.0

Base score 7.5 · High

Base metrics

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

Scores

Parameter	Value
Base score	7.5 · High
Exploitability score	-
Impact score	-

Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H