CVE-2026-77639

MEDIUM CVSS 3.1: 5.3 EPSS 0.23%
Updated Sep 08, 2026
Torproject
Parameter Value
CVSS 5.3 (MEDIUM)
Affected Versions 0.3.1.1-alpha — 0.4.9.9
Fixed In 0.4.9.9
Type CWE-420
Vendor Torproject
Public PoC No

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.

Attack Parameters

Attack Vector
Network
Can be exploited remotely
Attack Complexity
Low
Easy to exploit
Privileges Required
None
No privileges needed
User Interaction
None
No user interaction needed

Impact Assessment

Confidentiality
None
No data leak
Integrity
None
No data modification
Availability
Low
Partial disruption

CVSS Vector v3.1

Weakness Type (CWE)

Vulnerable Products 1

Configuration From (including) Up to (excluding)
Torproject Tor
cpe:2.3:a:torproject:tor:*:*:*:*:*:*:*:*
0.3.1.1-alpha 0.4.9.9