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 products
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| torprject | Tor | 0.4.9.3-alpha – < 0.4.9.12 | 0.4.9.12 |
Fixed in Linux distributions
Distributions backport fixes, so the version that fixes this vulnerability differs per release — upgrade to at least the version shown. From the distributions' security trackers and advisories.
Debian
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian 14 | tor | 0.4.9.12-2 | — |
| Debian 13 | tor | 0.4.9.12-0+deb13u2 | — |
| Debian 12 | tor | No fix yet | — |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 26.10 | tor | No fix yet | — |
| Ubuntu 26.04 LTS | tor | No fix yet | — |
| Ubuntu 24.04 LTS | tor | No fix yet | — |
| Ubuntu 22.04 LTS | tor | No fix yet | — |
Show 4 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu Pro 20.04 LTS | tor | No fix yet | — |
| Ubuntu Pro 18.04 LTS | tor | No fix yet | — |
| Ubuntu Pro 16.04 LTS | tor | No fix yet | — |
| Ubuntu Pro 14.04 LTS | tor | No fix yet | — |
openSUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| openSUSE Tumbleweed | tor | 0.4.9.13-1.1 | openSUSE-SU-2026:11909-1 |
Advisories 2
- openSUSE-SU-2026:11909-1 tor-0.4.9.13-1.1 on GA media SUSE / openSUSE Security Updates · Sep 29, 2026
- WID-SEC-2026-3279 Tor: Mehrere Schwachstellen BSI CERT-Bund (WID) · Sep 16, 2026