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.
Attack Parameters
Attack Vector
Network
Can be exploited remotely
Attack Complexity
Low
Easy to exploit
Privileges Required
None
No privileges needed
User Interaction
None
No user interaction needed
Impact Assessment
Confidentiality
None
No data leak
Integrity
None
No data modification
Availability
High
Complete denial of service
CVSS Vector v3.1
Weakness Type (CWE)
Vulnerable Products 12
| Configuration | From (including) | Up to (excluding) |
|---|---|---|
|
Varnish-Software Varnish_Enterprise
cpe:2.3:a:varnish-software:varnish_enterprise:*:*:*:*:*:*:*:*
|
— |
<= 6.0.15
|
|
Varnish-Software Varnish_Enterprise
cpe:2.3:a:varnish-software:varnish_enterprise:6.0.16:r1:*:*:*:*:*:*
|
— | — |
|
Varnish-Software Varnish_Enterprise
cpe:2.3:a:varnish-software:varnish_enterprise:6.0.16:r10:*:*:*:*:*:*
|
— | — |
|
Varnish-Software Varnish_Enterprise
cpe:2.3:a:varnish-software:varnish_enterprise:6.0.16:r2:*:*:*:*:*:*
|
— | — |
|
Varnish-Software Varnish_Enterprise
cpe:2.3:a:varnish-software:varnish_enterprise:6.0.16:r3:*:*:*:*:*:*
|
— | — |
|
Varnish-Software Varnish_Enterprise
cpe:2.3:a:varnish-software:varnish_enterprise:6.0.16:r4:*:*:*:*:*:*
|
— | — |
|
Varnish-Software Varnish_Enterprise
cpe:2.3:a:varnish-software:varnish_enterprise:6.0.16:r5:*:*:*:*:*:*
|
— | — |
|
Varnish-Software Varnish_Enterprise
cpe:2.3:a:varnish-software:varnish_enterprise:6.0.16:r6:*:*:*:*:*:*
|
— | — |
|
Varnish-Software Varnish_Enterprise
cpe:2.3:a:varnish-software:varnish_enterprise:6.0.16:r7:*:*:*:*:*:*
|
— | — |
|
Varnish-Software Varnish_Enterprise
cpe:2.3:a:varnish-software:varnish_enterprise:6.0.16:r8:*:*:*:*:*:*
|
— | — |
|
Varnish-Software Varnish_Enterprise
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:*:*:*:*:*:*:*
|
— | — |