CVE-2021-28089
HIGHCVSS 7.5/10EPSS 1.67%
Last modified
CVE-2021-28089 is a high-severity vulnerability rated 7.5/10 on the CVSS scale. 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.. EPSS estimates a 1.67% chance of exploitation in the next 30 days.
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.
Metrics
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Weakness Enumeration
Affected Software
| Vendor | Product | Versions | Update |
|---|---|---|---|
| Torproject | Tor | < 0.3.5.14 | — |
| Torproject | Tor | >= 0.4.4.4, < 0.4.4.8 | — |
| Torproject | Tor | >= 0.4.5.0, < 0.4.5.7 | — |
| Torproject | Tor | 0.4.4.0 | Alpha |
| Torproject | Tor | 0.4.4.1 | Alpha |
| Torproject | Tor | 0.4.4.2 | Alpha |
| Torproject | Tor | 0.4.4.3 | Alpha |
| Fedoraproject | Fedora | 33 | — |
References
- https://blog.torproject.org/node/2009Release Notes, Vendor Advisory
- https://gitlab.torproject.org/tpo/core/tor/-/issues/40304Vendor Advisory
- https://security.gentoo.org/glsa/202107-25Third Party Advisory
- https://blog.torproject.org/node/2009Release Notes, Vendor Advisory
- https://gitlab.torproject.org/tpo/core/tor/-/issues/40304Vendor Advisory
- https://security.gentoo.org/glsa/202107-25Third Party Advisory
Timeline
- Published
- Last Modified
- Status
- Modified
Frequently Asked Questions
What is CVE-2021-28089?
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.
How severe is CVE-2021-28089?
CVE-2021-28089 has a CVSS score of 7.5/10 (HIGH severity). The EPSS model estimates a 1.67% probability of exploitation in the next 30 days.
How do I fix CVE-2021-28089?
Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.
How Strix Helps
- How Strix found a critical auth bypass in etcdStrix autonomously discovered a critical authentication bypass in etcd, later designated CVE-2026-33413.
- Autonomous PentestingAI agents that find and validate exploitable vulnerabilities like this one across your applications.
- PR ReviewsPentest every pull request so vulnerable code is caught before it ships to production.
- AI Penetration TestingHow AI-driven penetration testing continuously covers your attack surface.
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Are you affected by CVE-2021-28089?
Run a free Strix scan to check your systems for this vulnerability.
Scan your code nowSource: NVD / NIST