Tor Use-After-Free in conflux component before 0.4.9.11
CVE-2026-77587 Published on August 20, 2026
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.
Vulnerability Analysis
CVE-2026-77587 can be exploited with network access, and does not require authorization privileges or user interaction. This vulnerability is consided to have a high level of attack complexity. The potential impact of an exploit of this vulnerability is considered to have no impact on confidentiality and integrity, and a high impact on availability.
Weakness Type
Improper Update of Reference Count
The software uses a reference count to manage a resource, but it does not update or incorrectly updates the reference count. Reference counts can be used when tracking how many objects contain a reference to a particular resource, such as in memory management or garbage collection. When the reference count reaches zero, the resource can be de-allocated or reused because there are no more objects that use it. If the reference count accidentally reaches zero, then the resource might be released too soon, even though it is still in use. If all objects no longer use the resource, but the reference count is not zero, then the resource might not ever be released.
Products Associated with CVE-2026-77587
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Affected Versions
torproject Tor:- Version 0.4.8.1-alpha and below 0.4.9.11 is affected.