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Low · 2.3 CVE-2026-93894 EUVD-2026-83400GHSA-pfj3-384h-g8q8

In Vinyl Cache before 9.0,2, workspace buffer overflow vulnerability was found in the .upper() and .lower() string type methods of VCL. Thi…

Published Sep 18, 2026 · Updated Sep 19, 2026 · Assigned by mitre

Description

In Vinyl Cache before 9.0,2, workspace buffer overflow vulnerability was found in the .upper() and .lower() string type methods of VCL. This can be used as a remote denial of service (DoS) vector to make the child process segfault or assert, and then restart. Effectively exploiting this vulnerability requires prior knowledge about the VCL in use and the ability to craft a request that contains a string that is long enough to fill the remaining workspace at the call site while staying under the different request size limits (http_req_size, http_req_hdr_len, etc.).

Affected products

VendorProductAffectedFixed
Vinyl-Cache Vinyl Cache < 9.0.2 9.0.2
Varnish-Software Varnish Cache 9.0.0 – < 9.0.4, 6.3.0 – ≤ 8.0.2 9.0.4

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.

ReleasePackageFixed inAdvisory
Debian 14 vinyl-cache 9.0.1-4.1 —
Debian 13 varnish 7.7.0-3+deb13u2 —
Debian 12 varnish No fix yet —
ReleasePackageFixed inAdvisory
Ubuntu 26.10 varnish +1 No fix yet —
Ubuntu 26.04 LTS 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)
ReleasePackageFixed inAdvisory
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

References