Linux Distros Unpatched Vulnerability : CVE-2026-11856

critical Nessus Plugin ID 322463

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.

- Successfully using libcurl to do a transfer to a specific HTTP origin (`hostA`) with **Digest** authentication and then changing the origin to a different one (`hostB`) for a second transfer, reusing the same handle, makes libcurl wrongly pass on the `Authorization:` header field meant for `hostA`, to `hostB`. (CVE-2026-11856)

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-2026-11856

https://security-tracker.debian.org/tracker/CVE-2026-11856

https://ubuntu.com/security/CVE-2026-11856

Plugin Details

Severity: Critical

ID: 322463

File Name: unpatched_CVE_2026_11856.nasl

Version: 1.5

Type: Local

Agent: unix

Family: Misc.

Published: 6/24/2026

Updated: 7/9/2026

Supported Sensors: Agentless Assessment, Frictionless Assessment Agent, Frictionless Assessment AWS, Frictionless Assessment Azure, Nessus Agent, Tenable Cloud Security, Tenable Self-Hosted Container Security, Nessus

Risk Information

VPR

Risk Factor: Medium

Score: 6.9

Percentile: 96.92

CVSS v2

Risk Factor: Medium

Base Score: 5

Temporal Score: 4.5

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

CVSS Score Source: CVE-2026-11856

CVSS v3

Risk Factor: Critical

Base Score: 9.8

Temporal Score: 9.3

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

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

Vulnerability Information

CPE: cpe:/o:debian:debian_linux:11.0, cpe:/o:redhat:enterprise_linux:8, cpe:/o:canonical:ubuntu_linux:18.04:-:lts, cpe:/o:canonical:ubuntu_linux:16.04:-:lts, cpe:/o:canonical:ubuntu_linux:20.04:-:lts, p-cpe:/a:centos:centos:curl, p-cpe:/a:centos:centos:libcurl, p-cpe:/a:centos:centos:libcurl-devel, p-cpe:/a:debian:debian_linux:curl, p-cpe:/a:redhat:enterprise_linux:curl, p-cpe:/a:redhat:enterprise_linux:libcurl, p-cpe:/a:redhat:enterprise_linux:libcurl-devel, p-cpe:/a:redhat:enterprise_linux:libcurl-minimal, p-cpe:/a:canonical:ubuntu_linux:curl, cpe:/o:centos:centos:8, p-cpe:/a:centos:centos:libcurl-minimal, cpe:/o:canonical:ubuntu_linux:14.04:-:lts, cpe:/o:canonical:ubuntu_linux:22.04:-:lts, cpe:/o:redhat:enterprise_linux:9, p-cpe:/a:redhat:enterprise_linux:curl-minimal, cpe:/o:debian:debian_linux:12.0, p-cpe:/a:centos:centos:curl-minimal, cpe:/o:canonical:ubuntu_linux:24.04:-:lts, cpe:/o:debian:debian_linux:13.0, cpe:/o:redhat:enterprise_linux:10, cpe:/o:debian:debian_linux:14.0, cpe:/o:canonical:ubuntu_linux:25.10, cpe:/o:canonical:ubuntu_linux:26.04:-:lts

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

Exploit Available: true

Exploit Ease: Exploits are available

Reference Information

CVE: CVE-2026-11856