Vulnerability · Published Jun 3, 2026 · Assigned by mitre
CVE-2026-50052
Low 2.3
In plain English
A low-severity security flaw in Varnish Cache (pre split) from The Vinyl Cache Project. 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 32% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Official 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 packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian:13 | varnish | 7.7.0-3+deb13u1 | DEBIAN-CVE-2026-50052 |
| Ubuntu:24.04:LTS | varnish | no fix listed | UBUNTU-CVE-2026-50052 |
| Ubuntu:25.10 | varnish | no fix listed | UBUNTU-CVE-2026-50052 |
| Ubuntu:26.04:LTS | varnish | no fix listed | UBUNTU-CVE-2026-50052 |
| Ubuntu:26.10 | varnish | no fix listed | UBUNTU-CVE-2026-50052 |
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| The Vinyl Cache Project | Vinyl Cache | 9.0.0 |
| The Vinyl Cache Project | Varnish Cache (pre split) | 7.6.0 – through 8.0.16.0.14 – through 6.0.17 |
| Varnish Software | Varnish Cache by Varnish Software | 9.0.0 – through 9.0.2 |
Weakness: CWE-444 · Vector: CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:P/VC:L/VI:N/VA:N/SC:L/SI:N/SA:N/S:N/AU:N/R:A/V:D/RE:L/U:Green