CVE-2026-77640
CVSS Score
3.7
EPSS Score
0.0%
EPSS Percentile
0th
tor before 0.4.9.9 was prone to an infinite loop when decompressing a truncated zlib/gzip stream with done=1. A truncated stream never reaches Z_STREAM_END, causing zlib to return Z_BUF_ERROR with no input remaining, which buf_add_compress() mistook for a full output buffer and retried forever. Fixed by returning TOR_COMPRESS_ERROR in that case so the caller can abort cleanly. This is TROVE-2026-021.
| CWE | CWE-1284 |
| Vendor | torproject |
| Product | tor |
| Published | Aug 20, 2026 |
Stay Ahead of the Next One
Get instant alerts for torproject tor
Be the first to know when new low vulnerabilities affecting torproject tor are published — delivered to Slack, Telegram or Discord.
Get Free Alerts →
Free · No credit card · 60 sec setup
CVSS v3 Breakdown
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:L Attack Vector
Network
Attack Complexity
High
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
Low
Affected Versions
torproject / Tor
0.2.6.1-alpha < 0.4.9.9