Vulnerability · Published Sep 9, 2026 · Assigned by mitre
CVE-2026-87724
Medium 6.5
In plain English
A medium-severity security flaw in Tor from torprject. 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 37% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Severity (CVSS 3.1)6.5Medium
Exploit odds (30 days)0.4%top 62.7% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack toolingNoneno public tooling known
Official description
Tor before 0.4.9.12 interprets the CC_RESPONSE extension even when CC_REQUEST was not sent, which allows remote attackers to cause a denial of service (crash) because of corrupted congestion-control state. This is TROVE-2026-032.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian:12 | tor | no fix listed | DEBIAN-CVE-2026-87724 |
| Debian:13 | tor | 0.4.9.12-0+deb13u2 | DEBIAN-CVE-2026-87724 |
| Debian:14 | tor | 0.4.9.12-2 | DEBIAN-CVE-2026-87724 |
| Ubuntu:22.04:LTS | tor | no fix listed | UBUNTU-CVE-2026-87724 |
| Ubuntu:24.04:LTS | tor | no fix listed | UBUNTU-CVE-2026-87724 |
| Ubuntu:26.04:LTS | tor | no fix listed | UBUNTU-CVE-2026-87724 |
| Ubuntu:26.10 | tor | no fix listed | UBUNTU-CVE-2026-87724 |
Affected products (as reported)
Weakness: CWE-669 · Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:H