Resource exhaustion in Torproject Tor

CVE-2021-34549

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.

Vulnerability class: DoS (Denial of Service)

EPSS: 0.016 (73.2th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 7.5 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H.

Affected products

Weakness classification (CWE)

References

Frequently asked questions

What is CVE-2021-34549?
CVE-2021-34549 is a high-severity vulnerability in Torproject Tor, classified under Uncontrolled Resource Consumption. CVSS score: 7.5/10. Published 2021-06-29.
How severe is CVE-2021-34549?
High severity. CVSS v3 base score is 7.5 out of 10.