CVE-2026-40394
Full vulnerability record from the local CVENow database.
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.
Severity
HIGH
CVSS score
7.5
(v3.1)
Vulnerability status
Analyzed
Source identifier
Published
2026-04-12 20:16:17.857000
Last modified
2026-10-26 21:10:00.170000
View original CVE JSON
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"sourceIdentifier": "[email protected]",
"published": "2026-04-12T20:16:17.857",
"lastModified": "2026-10-26T21:10:00.170",
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"affected": [
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"source": "[email protected]",
"affectedData": [
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