What’s Vulnerable › Vulnerabilities
CVE-2026-77641
- Severity: high (CVSS 8.2 v3.1)
- Exploited in the wild: not listed in CISA KEV
- EPSS: 0.4% probability of exploitation in the next 30 days
- Public exploit or detection template: none known
- Published: 2026-08-20 · updated 2026-10-18
- Weakness: CWE-252
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: before 0.4.9.9 — fixed in 0.4.9.9
How to fix
Upgrade to a fixed version: torproject Tor 0.4.9.9. Check the vendor advisory for mitigations.
References
Get alerted when CVE-2026-77641 or the next vulnerability affects your stack