High severity · published Aug 20, 2026
CVE-2026-77584
Tor before 0.4.9.10 did not reject a CONFLUX_LINK cell that arrives on a circuit which already has attached streams
8.2
CVSS
0.2%
EPSS
No
On KEV
Description
Tor before 0.4.9.10 did not reject a CONFLUX_LINK cell that arrives on a circuit which already has attached streams. A malicious client could send a RELAY_COMMAND_BEGIN before the CONFLUX_LINK on the same circuit, attaching an exit stream that would later end up orphan leaving a dangling circuit back-pointer and a use-after-free (UAF) when the circuit is freed. This is TROVE-2026-025.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:L
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Confidentiality
None
Integrity
High
Availability
Low
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.2% · higher than 16% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
TO
Tor · torproject
0.4.8.1-alpha before 0.4.9.10 · source: vendor, NVD
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-77584
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-77584
Release Notes
https://gitlab.torproject.org/tpo/core/tor/-/raw/tor-0.4.9.10/ChangeLog
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