CVE-2026-77639
Last modified
CVE-2026-77639 is a medium-severity vulnerability rated 5.3/10 on the CVSS scale. Tor before 0.4.9.9 was prone to a compression bomb bypass where an attacker could concatenate many gzip or zlib sub-streams, each just under the per-stream detection threshold, to avoid the compression bomb check entirely. This is TROVE-2026-022.. EPSS estimates a 0.39% chance of exploitation in the next 30 days.
Description
Tor before 0.4.9.9 was prone to a compression bomb bypass where an attacker could concatenate many gzip or zlib sub-streams, each just under the per-stream detection threshold, to avoid the compression bomb check entirely. This is TROVE-2026-022.
Metrics
Weakness Enumeration
Affected Software
| Vendor | Product | Versions |
|---|---|---|
| Torproject | Tor | < 0.4.9.9 |
References
- https://gitlab.torproject.org/tpo/core/tor/-/raw/tor-0.4.9.9/ChangeLogRelease Notes, Vendor Advisory
Timeline
- Published
- Last Modified
- Status
- Analyzed
Frequently Asked Questions
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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.
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