Description
Varnish Cache before 8.0.1 and Varnish Enterprise before 6.0.16r12, in certain unchecked req.url scenarios, mishandle URLs with a path of / for HTTP/1.1, potentially leading to cache poisoning or authentication bypass.
Affected products
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| varnish-software | Varnish Cache | < 6.0.17 LTS, 7.0.0 – < 8.0.1 | 6.0.17 LTS |
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+deb13u2 | — |
| Debian 12 | varnish | No fix yet | — |
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 | — |
Advisories 1
- WID-SEC-2026-0749 Varnish HTTP Cache: Schwachstelle ermöglicht Umgehen von Sicherheitsvorkehrungen BSI CERT-Bund (WID) · Oct 25, 2026