Resource exhaustion in Tor - CVE-2021-28089
Published: March 17, 2021
Vulnerability identifier: #VU51541
CSH Severity: Medium
CVSS v4: 8.7 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N]
CVE-ID: CVE-2021-28089
CWE-ID: CWE-400
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a remote attacker to perform a denial of service (DoS) attack.
The vulnerability exists due to application does not properly control consumption of internal resources when processing directory data. A remote attacker can force the Tor instance do consume huge amounts of CPU resources and perform a denial of service (DoS) attack.
Affected software
Tor
Gentoo Linux
Fedora
tor (Debian package)
tor
Gentoo Linux
Fedora
tor (Debian package)
tor
How to mitigate CVE-2021-28089
Install updates from vendor's website.
Tor - addressed in versions 0.3.5.14, 0.4.4.8, 0.4.5.7
tor (Debian package) - update to 0.3.5.14-1
tor - addressed in versions 0.3.5.14-1.el7, 0.4.5.7-1.fc33
tor (Debian package) - update to 0.3.5.14-1
tor - addressed in versions 0.3.5.14-1.el7, 0.4.5.7-1.fc33