VYPR
Get started
← All advisories
Medium severity4.0NVD Advisory· Published Apr 12, 2026· Updated Apr 17, 2026

CVE-2026-40394

CVE-2026-40394

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 products

12
  • Varnish Software/Varnish Enterprise11 versions
    cpe:2.3:a:varnish-software:varnish_enterprise:6.0.16:r5:*:*:*:*:*:*+ 10 more
    • cpe:2.3:a:varnish-software:varnish_enterprise:6.0.16:r5:*:*:*:*:*:*
    • cpe:2.3:a:varnish-software:varnish_enterprise:6.0.16:r6:*:*:*:*:*:*
    • cpe:2.3:a:varnish-software:varnish_enterprise:*:*:*:*:*:*:*:*range: <=6.0.15
    • cpe:2.3:a:varnish-software:varnish_enterprise:6.0.16:r1:*:*:*:*:*:*
    • cpe:2.3:a:varnish-software:varnish_enterprise:6.0.16:r10:*:*:*:*:*:*
    • cpe:2.3:a:varnish-software:varnish_enterprise:6.0.16:r2:*:*:*:*:*:*
    • cpe:2.3:a:varnish-software:varnish_enterprise:6.0.16:r3:*:*:*:*:*:*
    • cpe:2.3:a:varnish-software:varnish_enterprise:6.0.16:r4:*:*:*:*:*:*
    • cpe:2.3:a:varnish-software:varnish_enterprise:6.0.16:r7:*:*:*:*:*:*
    • cpe:2.3:a:varnish-software:varnish_enterprise:6.0.16:r8:*:*:*:*:*:*
    • cpe:2.3:a:varnish-software:varnish_enterprise:6.0.16:r9:*:*:*:*:*:*
  • Vinyl Cache/Vinyl Cache
    cpe:2.3:a:vinyl-cache:vinyl_cache:9.0.0:*:*:*:*:*:*:*

Patches

0

No patches discovered yet.

Vulnerability mechanics

AI mechanics synthesis has not run for this CVE yet.

References

1

News mentions

0

No linked articles in our index yet.