UBUNTU-CVE-2026-40394

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Source
https://ubuntu.com/security/CVE-2026-40394
Import Source
https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-40394.json
JSON Data
https://api.osv.dev/v1/vulns/UBUNTU-CVE-2026-40394
Upstream
  • CVE-2026-40394
Published
2026-04-12T20:16:00Z
Modified
2026-05-20T16:25:39.959227707Z
Severity
  • 4.0 (Medium) CVSS_V3 - CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:N/I:N/A:L CVSS Calculator
  • 7.5 (High) CVSS_V3 - CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H CVSS Calculator
  • Ubuntu - medium
Summary
[none]
Details

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.

References

Affected packages

Ubuntu:14.04:LTS
varnish

Package

Name
varnish
Purl
pkg:deb/ubuntu/varnish?arch=source&distro=trusty

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0Unknown introduced version / All previous versions are affected

Affected versions

3.*
3.0.4-1ubuntu1
3.0.4-1ubuntu2
3.0.5-1ubuntu2
3.0.5-2
3.0.5-2ubuntu0.1

Ecosystem specific 

{
    "binaries": [
        {
            "binary_name": "libvarnishapi1",
            "binary_version": "3.0.5-2ubuntu0.1"
        },
        {
            "binary_name": "varnish",
            "binary_version": "3.0.5-2ubuntu0.1"
        }
    ]
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-40394.json"
Ubuntu:24.04:LTS
varnish

Package

Name
varnish
Purl
pkg:deb/ubuntu/varnish?arch=source&distro=noble

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0Unknown introduced version / All previous versions are affected

Affected versions

7.*
7.1.1-1.1ubuntu1

Ecosystem specific 

{
    "binaries": [
        {
            "binary_name": "libvarnishapi3",
            "binary_version": "7.1.1-1.1ubuntu1"
        },
        {
            "binary_name": "varnish",
            "binary_version": "7.1.1-1.1ubuntu1"
        }
    ]
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-40394.json"
Ubuntu:25.10
varnish

Package

Name
varnish
Purl
pkg:deb/ubuntu/varnish?arch=source&distro=questing

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0Unknown introduced version / All previous versions are affected

Affected versions

7.*
7.7.0-1
7.7.0-2
7.7.0-3
7.7.3-1

Ecosystem specific 

{
    "binaries": [
        {
            "binary_name": "libvarnishapi3",
            "binary_version": "7.7.3-1"
        },
        {
            "binary_name": "varnish",
            "binary_version": "7.7.3-1"
        }
    ]
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-40394.json"
Ubuntu:26.04:LTS
varnish

Package

Name
varnish
Purl
pkg:deb/ubuntu/varnish?arch=source&distro=resolute

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0Unknown introduced version / All previous versions are affected

Affected versions

7.*
7.7.3-1
7.7.3-1build1

Ecosystem specific 

{
    "binaries": [
        {
            "binary_name": "libvarnishapi3",
            "binary_version": "7.7.3-1build1"
        },
        {
            "binary_name": "varnish",
            "binary_version": "7.7.3-1build1"
        }
    ]
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-40394.json"
Ubuntu:Pro:16.04:LTS
varnish

Package

Name
varnish
Purl
pkg:deb/ubuntu/varnish?arch=source&distro=esm-apps%2Fxenial

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0Unknown introduced version / All previous versions are affected

Affected versions

4.*
4.0.3-1
4.1.0-1
4.1.0-2
4.1.1-1
4.1.1-1ubuntu0.2
4.1.1-1ubuntu0.2+esm1

Ecosystem specific 

{
    "binaries": [
        {
            "binary_name": "libvarnishapi1",
            "binary_version": "4.1.1-1ubuntu0.2+esm1"
        },
        {
            "binary_name": "varnish",
            "binary_version": "4.1.1-1ubuntu0.2+esm1"
        }
    ]
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-40394.json"
Ubuntu:Pro:18.04:LTS
varnish

Package

Name
varnish
Purl
pkg:deb/ubuntu/varnish?arch=source&distro=esm-apps%2Fbionic

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0Unknown introduced version / All previous versions are affected

Affected versions

5.*
5.0.0-7.1
5.2.1-1
5.2.1-1ubuntu0.1
5.2.1-1ubuntu0.1+esm1

Ecosystem specific 

{
    "binaries": [
        {
            "binary_name": "libvarnishapi1",
            "binary_version": "5.2.1-1ubuntu0.1+esm1"
        },
        {
            "binary_name": "varnish",
            "binary_version": "5.2.1-1ubuntu0.1+esm1"
        }
    ]
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-40394.json"
Ubuntu:Pro:20.04:LTS
varnish

Package

Name
varnish
Purl
pkg:deb/ubuntu/varnish?arch=source&distro=esm-apps%2Ffocal

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0Unknown introduced version / All previous versions are affected

Affected versions

6.*
6.1.1-1
6.2.1-2
6.2.1-2ubuntu0.1~esm1
6.2.1-2ubuntu0.1~esm2
6.2.1-2ubuntu0.1
6.2.1-2ubuntu0.2
6.2.1-2ubuntu0.2+esm1

Ecosystem specific 

{
    "binaries": [
        {
            "binary_name": "libvarnishapi2",
            "binary_version": "6.2.1-2ubuntu0.2+esm1"
        },
        {
            "binary_name": "varnish",
            "binary_version": "6.2.1-2ubuntu0.2+esm1"
        }
    ]
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-40394.json"
Ubuntu:Pro:22.04:LTS
varnish

Package

Name
varnish
Purl
pkg:deb/ubuntu/varnish?arch=source&distro=esm-apps%2Fjammy

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0Unknown introduced version / All previous versions are affected

Affected versions

6.*
6.5.2-1
6.6.1-1
6.6.1-1ubuntu0.2
6.6.1-1ubuntu0.2+esm1

Ecosystem specific 

{
    "binaries": [
        {
            "binary_name": "libvarnishapi2",
            "binary_version": "6.6.1-1ubuntu0.2+esm1"
        },
        {
            "binary_name": "varnish",
            "binary_version": "6.6.1-1ubuntu0.2+esm1"
        }
    ]
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-40394.json"