# CVE-2026-77587: Tor use-after-free in conflux object recovery

Source: https://junglewise.ai/threats/cve-2026-77587-tor-use-after-free-in-conflux-object-recovery  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-08-20. Updated: 2026-09-25  
License: CC BY 4.0 with a link back

CVE-2026-77587 · Severity: medium · CVSS 5.9 · Published 2026-08-20

Tor is anonymity software used by millions to protect their privacy and evade censorship. A bug in how Tor handles network circuit recovery could allow a malicious exit node (an internet relay point) to crash a user's Tor client, disrupting their connection and potentially revealing their real IP address or making them unavailable temporarily.

Technologies: [Torproject Tor](https://junglewise.ai/threats/technologies/tor). Vendors: [Torproject](https://junglewise.ai/threats/vendors/torproject).

## Quick answers

**Is CVE-2026-77587 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-77587 being exploited in the wild.

**How severe is CVE-2026-77587?** Medium severity, with a CVSS score of 5.9, published 20 August 2026.

**Which products and versions are affected?** Tor Project Tor before 0.4.9.11.

**Is there a fix for CVE-2026-77587?** No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.

**How is CVE-2026-77587 attacked?** It is attacked over the network.

**Am I affected by CVE-2026-77587?** Check whether you run Torproject Tor. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## Technical details

A use-after-free and potential double-free vulnerability exists in Tor's conflux object handling when a recovery leg revives a conflux set whose last linked leg has already been closed. The flaw is in the memory management logic that governs circuit recovery in Tor's conflux (parallel circuits) feature. The attack requires a malicious exit node in the target user's circuit, which is reachable over the network. Successful exploitation crashes the Tor client, causing a denial of service. The vulnerability is fixed in Tor 0.4.9.11 and later versions.

## Affected products

- Tor Project Tor before 0.4.9.11

## Timeline

- 2026-08-20: disclosed

## References

- [https://gitlab.torproject.org/tpo/core/tor/-/raw/tor-0.4.9.11/ChangeLog](https://gitlab.torproject.org/tpo/core/tor/-/raw/tor-0.4.9.11/ChangeLog)

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