tor: tor before 0.4.9.9 was prone to a NULL write after free when sending a CONFLUX_SWITCH cell fails
CVE-2026-77641 is fixed in tor on 1 platform, first by DEBIAN-CVE-2026-77641, released August 21, 2026. It is not reported as exploited. Patch Radar priority: High.
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.
Where it's fixed
| Product | Fixed in | Fix | Released |
|---|---|---|---|
| Linux | |||
| tor · Debian 12.15 (bookworm) | 0.4.9.9-1 | DEBIAN-CVE-2026-77641 | Aug 21, 2026 |
| tor · Debian 13.5 (trixie) | 0.4.9.11-0+deb13u1 | DEBIAN-CVE-2026-77641 | Aug 21, 2026 |
| tor · Debian 14 | 0.4.9.9-1 | DEBIAN-CVE-2026-77641 | Aug 21, 2026 |
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