CVE catalog

CVE-2026-40394

Severity: Medium · CVSS 5.9CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H
Published: Apr 12, 2026, 7:17:34 PM UTC
Source: [NVD] · [CVE record]
EPSS: 0.24% · Oct 25, 2026

Varnish Cache 9 before 9.0.1 and Varnish Enterprise before 6.0.16r11 allows a "workspace overflow" denial of service (daemon panic) for certain amounts of prefetched data. The setup of an HTTP/2 session starts with a speculative HTTP/1 transport, and upon upgrading to h2 the HTTP/1 request is repurposed as stream zero. During the upgrade, a buffer allocation is made to reserve space to send frames to the client. This allocation would split the original workspace, and depending on the amount of prefetched data, the next fetch could perform a pipelining operation that would run out of workspace.

Vulnerable and fixed packages

Distribution-reported package versions and fixes. These do not depend on matching against the OpenFactory package catalog.

Distribution	Package	Release	Version	Status
Debian	varnish	trixie	`7.7.0-3+deb13u1`	not affected
Debian	varnish	trixie-security	`7.7.0-3+deb13u2`	not affected
Debian	varnish	bookworm	`7.1.1-2+deb12u1`	not affected
Debian	varnish	bookworm-security	`7.1.1-2+deb12u1`	not affected
Cpe	varnish_enterprise	Not reported	Not reported	unknown
Cpe	vinyl_cache	Not reported	Not reported	unknown
Cpe	varnish_enterprise	Not reported	Not reported	unknown
Cpe	vinyl_cache	Not reported	Not reported	unknown

Fixed-version evidence

Distribution	Package	Type	Release	Fixed version	Urgency	Origin	Bugs
Debian	varnish	source	trixie	`Not affected`	unimportant	Not reported	Not reported
Debian	varnish	source	bookworm	`Not affected`	unimportant	Not reported	Not reported

OpenFactory catalog packages

[Debian 12 (Bookworm)]

[libvarnishapi3]Not affected
Source package: [varnish]
Details (4)
- 7.1.1-2+deb12u1 · amd64 · bookworm
  Not affected
  nvd · varnish · debian · bookworm
- 7.1.1-2+deb12u1 · arm64 · bookworm
  Not affected
  nvd · varnish · debian · bookworm
- 7.1.1-2+deb12u1 · amd64 · bookworm-security
  Not affected
  nvd · varnish · debian · bookworm
- 7.1.1-2+deb12u1 · arm64 · bookworm-security
  Not affected
  nvd · varnish · debian · bookworm
[libvarnishapi-dev]Not affected
Source package: [varnish]
Details (4)
- 7.1.1-2+deb12u1 · amd64 · bookworm
  Not affected
  nvd · varnish · debian · bookworm
- 7.1.1-2+deb12u1 · arm64 · bookworm
  Not affected
  nvd · varnish · debian · bookworm
- 7.1.1-2+deb12u1 · amd64 · bookworm-security
  Not affected
  nvd · varnish · debian · bookworm
- 7.1.1-2+deb12u1 · arm64 · bookworm-security
  Not affected
  nvd · varnish · debian · bookworm
[varnish]Not affected
Details (4)
- 7.1.1-2+deb12u1 · amd64 · bookworm
  Not affected
  nvd · varnish · debian · bookworm
- 7.1.1-2+deb12u1 · arm64 · bookworm
  Not affected
  nvd · varnish · debian · bookworm
- 7.1.1-2+deb12u1 · amd64 · bookworm-security
  Not affected
  nvd · varnish · debian · bookworm
- 7.1.1-2+deb12u1 · arm64 · bookworm-security
  Not affected
  nvd · varnish · debian · bookworm
[varnish-doc]Not affected
Source package: [varnish]
Details (4)
- 7.1.1-2+deb12u1 · all · bookworm
  Not affected
  nvd · varnish · debian · bookworm
- 7.1.1-2+deb12u1 · all · bookworm
  Not affected
  nvd · varnish · debian · bookworm
- 7.1.1-2+deb12u1 · all · bookworm-security
  Not affected
  nvd · varnish · debian · bookworm
- 7.1.1-2+deb12u1 · all · bookworm-security
  Not affected
  nvd · varnish · debian · bookworm

Observed: Oct 27, 2026, 7:59:11 AM UTC

References

[CERT-Bund public advisories] · [Debian Security Tracker] · [FIRST EPSS] · [National Vulnerability Database (NVD)] · [OSV Package Vulnerability Database] · [Red Hat security advisories and VEX]