CVE-2026-77641

EUVD-2026-63658
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.
ProviderTypeBase ScoreAtk. VectorAtk. ComplexityPriv. RequiredVector
NISTPrimary
6.5 MEDIUM
NETWORK
HIGH
NONE
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:H
Base Score
CVSS 3.x
EPSS Score
Percentile: 26.7%
Affected Products (NVD)
VendorProductVersion
torprojecttor
𝑥
< 0.4.9.9
𝑥
= Vulnerable software versions
Debian logo
Debian Releases
Debian Product
Codename
tor
bookworm
0.4.9.11-0+deb12u1
fixed
bookworm (security)
0.4.9.11-0+deb12u1
fixed
forky
0.4.9.12-4
fixed
sid
0.4.9.13-1
fixed
trixie
0.4.9.11-0+deb13u1
fixed
trixie (security)
0.4.9.13-0+deb13u1
fixed
Ubuntu logo
Ubuntu Releases
Ubuntu Product
Codename
tor
bionic
needs-triage
focal
needs-triage
jammy
needs-triage
noble
needs-triage
resolute
needs-triage
trusty
needs-triage
xenial
needs-triage