Use After Free in Torproject Tor
CVE-2026-77587
Tor before 0.4.9.11 is prone to a use-after-free (and potential double free) of a conflux object when a recovery leg revives a conflux set whose last linked leg has already been closed. A malicious exit node could use this to crash a client. This is TROVE-2026-026.
Published · last modified .
CVSS v3 metric
CVSS v3 base score 5.9 (Medium). Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H.
EPSS exploit prediction
EPSS: 0.004 (32.5th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 32nd percentile — 32.5% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.002 · newest: 0.004 · change: +0.002
Affected products
Weakness classification (CWE)
References
- gitlab.torproject.org/tpo/core/tor/-/raw/tor-0.4.9.11/ChangeLog (Permissions Required, Release Notes, Vendor Advisory)
Frequently asked questions
- What is CVE-2026-77587?
- CVE-2026-77587 is a medium-severity vulnerability in Torproject Tor, classified under CWE-911. CVSS score: 5.9/10. Published 2026-08-20.
- How severe is CVE-2026-77587?
- Medium severity. CVSS v3 base score is 5.9 out of 10.