CVE Vulnerabilities

CVE-2017-8823

Use After Free

Published: Dec 03, 2017 | Modified: Apr 20, 2025
CVSS 3.x
8.1
HIGH
Source:
NVD
CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
CVSS 2.x
6.8 MEDIUM
AV:N/AC:M/Au:N/C:P/I:P/A:P
RedHat/V2
RedHat/V3
Ubuntu
MEDIUM

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, there is a use-after-free in onion service v2 during intro-point expiration because the expiring list is mismanaged in certain error cases, aka TROVE-2017-013.

Weakness

The product reuses or references memory after it has been freed. At some point afterward, the memory may be allocated again and saved in another pointer, while the original pointer references a location somewhere within the new allocation. Any operations using the original pointer are no longer valid because the memory “belongs” to the code that operates on the new pointer.

Affected Software

Name Vendor Start Version End Version
Tor Tor_project * 0.2.5.16 (excluding)
Tor Tor_project 0.2.6 (including) 0.2.8.17 (excluding)
Tor Tor_project 0.2.9 (including) 0.2.9.14 (excluding)
Tor Tor_project 0.3.0 (including) 0.3.0.13 (excluding)
Tor Tor_project 0.3.1 (including) 0.3.1.9 (excluding)
Tor Ubuntu artful *
Tor Ubuntu esm-apps/xenial *
Tor Ubuntu upstream *
Tor Ubuntu xenial *
Tor Ubuntu zesty *

Potential Mitigations

References