CVEvulnerability

CVE-2026-40394

7.5 HIGH Published 2026-04-12 Modified 2026-10-26 Official page ↗
Status
Analyzed
Published
2026-04-12
Last modified
2026-10-26
Assigner
[email protected]
CVSS 3.1 ([email protected])
4.0 MEDIUM — CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:N/I:N/A:L
CVSS 3.1 ([email protected])
7.5 HIGH — CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Weaknesses
CWE-670

Description

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.

Affected configurations

• varnish-software varnish enterprise (<= 6.0.15) • varnish-software varnish enterprise 6.0.16 • vinyl-cache vinyl cache 9.0.0

Related

Weakness · CWE (1)

  • CWE-670 Always-Incorrect Control Flow Implementation weakness

References