Use-after-free in Tor - CVE-2017-8823
Published: December 3, 2017 / Updated: July 17, 2020
Vulnerability identifier: #VU31388
CSH Severity: High
CVSS v4: 9.2 [CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N]
CVE-ID: CVE-2017-8823
CWE-ID: CWE-416
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a remote non-authenticated attacker to execute arbitrary code.
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.
Affected software
Tor
Arch Linux
Fedora
tor
Arch Linux
Fedora
tor
How to mitigate CVE-2017-8823
Install update from vendor's website.
Tor - update to 0.3.1.9
tor - addressed in versions 0.2.9.14-1.el6, 0.2.9.14-1.el7, 0.3.1.9-1.fc26, 0.3.1.9-1.fc27
tor - addressed in versions 0.2.9.14-1.el6, 0.2.9.14-1.el7, 0.3.1.9-1.fc26, 0.3.1.9-1.fc27