Description
In Vinyl Cache before 9.0.1 and Varnish Cache before 9.0.3, a deficiency in HTTP/2 request parsing can be exploited to launch a backend request desync
attack (request smuggling), which in turn can be used for cache poisoning,
authentication bypass, or possibly even information disclosure and manipulation. The attack vector only exists if HTTP/2 support is enabled by setting the
feature parameter to contain +http2. HTTP/2 support is disabled by
default.
Affected products
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| The Vinyl Cache Project | Vinyl Cache | 9.0.0 | 9.0.1 |
| The Vinyl Cache Project | Varnish Cache (pre split) | 7.6.0 – ≤ 8.0.1, 6.0.14 – ≤ 6.0.17 | 8.0.2 |
| Varnish Software | Varnish Cache by Varnish Software | 9.0.0 – ≤ 9.0.2 | 9.0.3 |
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 13 | varnish | 7.7.0-3+deb13u1 | — |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 26.10 | varnish | No fix yet | — |
| Ubuntu 26.04 LTS | varnish | No fix yet | — |
| Ubuntu 25.10 | varnish | No fix yet | — |
| Ubuntu 24.04 LTS | varnish | No fix yet | — |
| Ubuntu 14.04 LTS | varnish | No fix yet | — |
Show 4 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu Pro 22.04 LTS | varnish | No fix yet | — |
| Ubuntu Pro 20.04 LTS | varnish | No fix yet | — |
| Ubuntu Pro 18.04 LTS | varnish | No fix yet | — |
| Ubuntu Pro 16.04 LTS | varnish | No fix yet | — |
openSUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| openSUSE Tumbleweed | vinyl-cache | 9.0.1-1.1 | openSUSE-SU-2026:11039-1 |
Advisories 2
- WID-SEC-2026-1576 Varnish HTTP Cache: Schwachstelle ermöglicht Manipulation von Dateien, Offenlegung von Informationen und Umgehen von Sicherheitsvrkehrungen BSI CERT-Bund (WID) · Aug 26, 2026
- openSUSE-SU-2026:11039-1 libvinylapi3-9.0.1-1.1 on GA media SUSE / openSUSE Security Updates · Jun 16, 2026