What’s Vulnerable › Vulnerabilities
CVE-2021-28089
- Severity: high (CVSS 7.5 v3.1)
- Exploited in the wild: not listed in CISA KEV
- EPSS: 1.7% probability of exploitation in the next 30 days
- Public exploit or detection template: none known
- Published: 2021-03-19 · updated 2026-06-17
- Weakness: CWE-400
Description
Tor before 0.4.5.7 allows a remote participant in the Tor directory protocol to exhaust CPU resources on a target, aka TROVE-2021-001.
Affected products
- Fedoraproject Fedora: 33
- torproject Tor: before 0.3.5.14; from 0.4.4.4 before 0.4.4.8; from 0.4.5.0 before 0.4.5.7; 0.4.4.0-alpha, 0.4.4.1-alpha, 0.4.4.2-alpha, 0.4.4.3-alpha — fixed in 0.3.5.14, 0.4.4.8, 0.4.5.7
How to fix
Upgrade to a fixed version: torproject Tor 0.3.5.14, 0.4.4.8, 0.4.5.7. Check the vendor advisory for mitigations.
References
- https://blog.torproject.org/node/2009
- https://gitlab.torproject.org/tpo/core/tor/-/issues/40304
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/HPDXB2GZHG3VNOTWSXQ3QZVHNV76WCU5/
- https://security.gentoo.org/glsa/202107-25
- https://blog.torproject.org/node/2009
- https://gitlab.torproject.org/tpo/core/tor/-/issues/40304
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/HPDXB2GZHG3VNOTWSXQ3QZVHNV76WCU5/
- https://security.gentoo.org/glsa/202107-25
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