Detections
Analytics

Linux Distros Unpatched Vulnerability : CVE-2026-40395

medium Nessus Plugin ID 306145

Synopsis

The Linux/Unix host has one or more packages installed with a vulnerability that the vendor indicates will not be patched.

Description

The Linux/Unix host has one or more packages installed that are impacted by a vulnerability without a vendor supplied patch available.

 - 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(<label>)) 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. (CVE-2026-40395)

Note that Nessus relies on the presence of the package as reported by the vendor.

Solution

There is no known solution at this time.

See Also

https://access.redhat.com/security/cve/cve-2026-40395

Plugin Details

Severity: Medium

ID: 306145

File Name: unpatched_CVE_2026_40395.nasl

Version: 1.1

Type: Local

Agent: unix

Family: Misc.

Published: 4/13/2026

Updated: 4/13/2026

Supported Sensors: Frictionless Assessment AWS, Frictionless Assessment Azure, Frictionless Assessment Agent, Nessus Agent, Agentless Assessment, Nessus

Risk Information

VPR

Risk Factor: Low

Score: 3.2

CVSS v2

Risk Factor: Medium

Base Score: 5

Temporal Score: 4.3

Vector: CVSS2#AV:N/AC:L/Au:N/C:N/I:N/A:P

CVSS Score Source: CVE-2026-40395

CVSS v3

Risk Factor: Medium

Base Score: 4

Temporal Score: 3.7

Vector: CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:C/C:N/I:N/A:L

Temporal Vector: CVSS:3.0/E:U/RL:U/RC:C

Vulnerability Information

CPE: cpe:/o:redhat:enterprise_linux:8, p-cpe:/a:redhat:enterprise_linux:varnish, p-cpe:/a:redhat:enterprise_linux:varnish-devel, p-cpe:/a:redhat:enterprise_linux:varnish-docs, p-cpe:/a:redhat:enterprise_linux:varnish-modules, cpe:/o:centos:centos:8, p-cpe:/a:centos:centos:varnish, p-cpe:/a:centos:centos:varnish-devel, p-cpe:/a:centos:centos:varnish-docs, p-cpe:/a:centos:centos:varnish-modules

Required KB Items: Host/local_checks_enabled, Host/cpu, global_settings/vendor_unpatched, Host/OS/identifier

Exploit Ease: No known exploits are available

Vulnerability Publication Date: 4/12/2026

Reference Information

CVE: CVE-2026-40395