Vulnerability in Torproject Tor

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. 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 v3 metric

CVSS v3 base score 7.0 (High). Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:H/A:L.

Affected products

Weakness classification (CWE)

References

Frequently asked questions

What is CVE-2026-77584?
CVE-2026-77584 is a high-severity vulnerability in Torproject Tor, classified under CWE-821. CVSS score: 7.0/10. Published 2026-08-20.
How severe is CVE-2026-77584?
High severity. CVSS v3 base score is 7.0 out of 10.