Description
tor before 0.4.9.9 was prone to a NULL write after free when sending a CONFLUX_SWITCH cell fails. The return value of relay_send_command_from_edge() was ignored, so a send failure (which calls circuit_mark_for_close() and removes the leg via cfx_del_leg()) would go undetected, causing the caller to write to the now-freed current leg and resulting in a crash. This is TROVE-2026-017.
Affected products
torproject: tor
References1
- gitlab.torproject.org/tpo/core/tor/-/raw/tor-0.4.9.9/ChangeLog Release NotesVendor Advisory
Metrics
- CVSS 3.1
-
8.2
HIGH
Score source: NVD
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:H - EPSS — exploit probability
- 0% percentile: 29 · as of 10 November 2026
- CWE
- CWE-252
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