UBUNTU-CVE-2026-40395

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Source

https://ubuntu.com/security/CVE-2026-40395

Import Source

https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-40395.json

JSON Data

https://api.osv.dev/v1/vulns/UBUNTU-CVE-2026-40395

Upstream

CVE-2026-40395

Published

2026-04-12T20:16:00Z

Modified

2026-05-20T16:25:39Z

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 Enterprise before 6.0.16r12 allows a "workspace overflow" denial of service (daemon panic) for shared VCL. The headerplus.write_req0() function from vmod_headerplus updates the underlying req0, which is normally the original read-only request from which req is derived (readable and writable from VCL). This is useful in the active VCL, after amending req, to prepare a refined req0 before switching to a different VCL with the return (vcl()) action. This is for example how the Varnish Controller operates shared VCL deployments. If the amended req contained too many header fields for req0, this would have resulted in a workspace overflow that would in turn trigger a panic and crash the Varnish Enterprise server. This could be used as a Denial of Service attack vector by malicious clients.

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

0 Unknown 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-2026-40395.json"

Ubuntu:24.04:LTS

varnish

Package

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

Affected ranges

Type: ECOSYSTEM
Events: Introduced

0 Unknown 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-2026-40395.json"

Ubuntu:25.10

varnish

Package

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

Affected ranges

Type: ECOSYSTEM
Events: Introduced

0 Unknown 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-2026-40395.json"

Ubuntu:26.04:LTS

varnish

Package

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

Affected ranges

Type: ECOSYSTEM
Events: Introduced

0 Unknown 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-2026-40395.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

0 Unknown 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-2026-40395.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

0 Unknown 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-2026-40395.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

0 Unknown 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-2026-40395.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

0 Unknown 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-2026-40395.json"