CVE-2026-77584
HIGHDescription
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.
How to fix
TridentStack Control can deploy fixes like this automatically across your Windows, macOS, and Linux fleet. See how it works
Remediation is compiled from vendor and distribution security advisories. Always confirm against the linked source for your exact version and platform.
CVSS v3 Vector
Exploitability
Impact
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:H/A:L
Exploit Intelligence
Low risk: more likely to be exploited than 7% of all known CVEs.
References
Related Vulnerabilities
Other CWE-821 vulnerabilities, ordered by exploit likelihood. View all
| CVE | Severity | CVSS | EPSS | Exploited | Fix |
|---|---|---|---|---|---|
| CVE-2022-1931 | High | 8.1 | 2.1% | - | Fix |
| CVE-2024-1739 | Critical | 9.1 | 0.6% | - | Fix |
| CVE-2024-1902 | High | 7.5 | 0.4% | - | Fix |
| CVE-2024-5755 | Medium | 5.3 | 0.3% | - | - |
| CVE-2026-43198 | Medium | 4.8 | 0.3% | - | Fix |
| CVE-2024-58133 | Medium | 4.0 | 0.3% | - | - |
Common questions
How do I fix CVE-2026-77584?
Upgrade tor on debian 13 to 0.4.9.11-0+deb13u1 or later.
Is CVE-2026-77584 being actively exploited?
Not that we know of. CVE-2026-77584 is not in the CISA Known Exploited Vulnerabilities catalog. Its EPSS score of 0.18% is the estimated probability that it will be exploited in the next 30 days. That is higher than 7% of all scored CVEs.
How severe is CVE-2026-77584?
CVE-2026-77584 has a CVSS v3 base score of 7.0, rated high. CVSS rates the technical impact if the vulnerability is exploited, not how likely that is, so weigh it alongside the exploit-prediction score when you decide what to patch first.
What does CVE-2026-77584 affect?
Published advisories record a fix for tor (Debian). Only products with a sourced advisory are listed, so treat this as what we can cite rather than a complete inventory.
Embed a live status badge for CVE-2026-77584
Markdown
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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2026-08-25.