Vulnerability · Published Aug 20, 2026 · Assigned by mitre
CVE-2026-77587
Medium 5.9
In plain English
A medium-severity security flaw in Tor from torproject. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.4% (higher than 35% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Severity (CVSS 3.1)5.9Medium
Exploit odds (30 days)0.4%top 65.0% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack toolingNoneno public tooling known
Official description
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.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian:12 | tor | 0.4.9.11-0+deb12u1 | DEBIAN-CVE-2026-77587 |
| Debian:13 | tor | 0.4.9.11-0+deb13u1 | DEBIAN-CVE-2026-77587 |
| Debian:14 | tor | 0.4.9.11-1 | DEBIAN-CVE-2026-77587 |
| Ubuntu:22.04:LTS | tor | no fix listed | UBUNTU-CVE-2026-77587 |
| Ubuntu:24.04:LTS | tor | no fix listed | UBUNTU-CVE-2026-77587 |
| Ubuntu:26.04:LTS | tor | no fix listed | UBUNTU-CVE-2026-77587 |
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| torproject | Tor | 0.4.8.1-alpha – before 0.4.9.11 |
Weakness: CWE-911 · Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H