CVE-2021-34549 Denial of service in n/a
An attacker can cause algorithm inefficiency and denial of service in Tor by triggering the use of an attacker-chosen circuit ID.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2021-34549?
CVE-2021-34549 is a high-severity denial of service vulnerability in n/a, published on 29 Jun 2021. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
An issue was discovered in Tor before 0.4.6.5, aka TROVE-2021-005. Hashing is mishandled for certain retrieval of circuit data. Consequently. an attacker can trigger the use of an attacker-chosen circuit ID to cause algorithm inefficiency.
Weakness: CWE-400
Which versions are affected by CVE-2021-34549?
It affects 1 product.
Products include Torproject Tor.
How do I fix CVE-2021-34549?
Upgrade to a fixed version.
Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.
Is CVE-2021-34549 being exploited?
There is no known exploitation of CVE-2021-34549 in the wild and no public exploit code.
Other vulnerabilities in n/a
Sources
Also known as DEBIAN-CVE-2021-34549, GHSA-qx32-4xrf-2j53, UBUNTU-CVE-2021-34549.