CVE-2026-77584: Use After Free
Tor before 0.4.9.10 did not reject a CONFLUXLINK cell that arrives on a circuit which already has attached streams. A malicious client could send a RELAYCOMMANDBEGIN before the CONFLUXLINK 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.
Affected Software
Event History
Frequently Asked Questions
Which Tor deployments are affected?
Tor versions before 0.4.9.10 are affected. The issue applies when a circuit processes a CONFLUX_LINK cell after streams have already been attached to that circuit.
What must an attacker do to trigger the flaw?
A malicious client must send a RELAY_COMMAND_BEGIN to attach an exit stream, then send a CONFLUX_LINK cell on the same circuit. This can leave the exit stream orphaned with a dangling circuit back-pointer, causing a use-after-free when the circuit is freed.