Linux Distros Unpatched Vulnerability : CVE-2026-6253

medium Nessus Plugin ID 311014

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.

- curl might erroneously pass on credentials for a first proxy to a second proxy. This can happen when the following conditions are true: 1. curl is setup to use specific different proxies for different URL schemes 2. the first proxy needs credentials 3. the second proxy uses no credentials 4. while using the first proxy (using say `http://`), curl is asked to follow a redirect to a URL using another scheme (say `https://`), accessed using a second, different, proxy (CVE-2026-6253)

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-2026-6253

https://security-tracker.debian.org/tracker/CVE-2026-6253

https://ubuntu.com/security/CVE-2026-6253

Plugin Details

Severity: Medium

ID: 311014

File Name: unpatched_CVE_2026_6253.nasl

Version: 1.8

Type: Local

Agent: unix

Family: Misc.

Published: 4/29/2026

Updated: 5/15/2026

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

Risk Information

VPR

Risk Factor: Medium

Score: 4.4

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-2026-6253

CVSS v3

Risk Factor: Medium

Base Score: 5.9

Temporal Score: 5.6

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

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

Vulnerability Information

CPE: cpe:/o:debian:debian_linux:11.0, p-cpe:/a:redhat:enterprise_linux:rust-std-static-x86_64-unknown-none, cpe:/o:canonical:ubuntu_linux:20.04:-:lts, p-cpe:/a:redhat:enterprise_linux:rust-analysis, p-cpe:/a:centos:centos:rustfmt, cpe:/o:redhat:enterprise_linux:6, p-cpe:/a:redhat:enterprise_linux:rust-src, p-cpe:/a:centos:centos:s390utils-osasnmpd, p-cpe:/a:redhat:enterprise_linux:rust-analyzer, p-cpe:/a:redhat:enterprise_linux:s390utils-base, p-cpe:/a:redhat:enterprise_linux:cargo, p-cpe:/a:redhat:enterprise_linux:s390utils-mon_statd, cpe:/o:redhat:enterprise_linux:9, p-cpe:/a:centos:centos:cargo, p-cpe:/a:centos:centos:rust-doc, p-cpe:/a:redhat:enterprise_linux:rust-gdb, p-cpe:/a:redhat:enterprise_linux:rust-lldb, p-cpe:/a:redhat:enterprise_linux:libcurl-devel, p-cpe:/a:centos:centos:clippy, p-cpe:/a:redhat:enterprise_linux:s390utils-cpuplugd, cpe:/o:redhat:enterprise_linux:10, p-cpe:/a:centos:centos:s390utils-cpacfstatsd, cpe:/o:canonical:ubuntu_linux:14.04:-:lts, p-cpe:/a:centos:centos:rust-toolset-srpm-macros, p-cpe:/a:redhat:enterprise_linux:rust-toolset-srpm-macros, p-cpe:/a:redhat:enterprise_linux:libcurl, p-cpe:/a:redhat:enterprise_linux:rust, cpe:/o:canonical:ubuntu_linux:16.04:-:lts, cpe:/o:redhat:enterprise_linux:7, p-cpe:/a:centos:centos:s390utils-mon_statd, p-cpe:/a:centos:centos:s390utils-cmsfs-fuse, p-cpe:/a:redhat:enterprise_linux:clippy, p-cpe:/a:centos:centos:libcurl, p-cpe:/a:redhat:enterprise_linux:s390utils, p-cpe:/a:centos:centos:rust-std-static-wasm32-unknown-unknown, p-cpe:/a:redhat:enterprise_linux:rust-std-static-wasm32-wasip1, p-cpe:/a:redhat:enterprise_linux:libcurl-minimal, p-cpe:/a:centos:centos:rust-std-static-x86_64-unknown-none, p-cpe:/a:redhat:enterprise_linux:rust-toolset, p-cpe:/a:centos:centos:snphost, p-cpe:/a:centos:centos:rust-analysis, p-cpe:/a:redhat:enterprise_linux:s390utils-cmsfs-fuse, p-cpe:/a:redhat:enterprise_linux:rust-std-static-wasm32-wasi, p-cpe:/a:centos:centos:rust-std-static-wasm32-wasip1, p-cpe:/a:redhat:enterprise_linux:trustee-guest-components, p-cpe:/a:redhat:enterprise_linux:rustfmt, p-cpe:/a:centos:centos:libcurl-devel, p-cpe:/a:redhat:enterprise_linux:s390utils-core, p-cpe:/a:centos:centos:rust-debugger-common, p-cpe:/a:centos:centos:trustee, p-cpe:/a:centos:centos:s390utils-devel, p-cpe:/a:centos:centos:s390utils-cpuplugd, p-cpe:/a:redhat:enterprise_linux:s390utils-zdsfs, p-cpe:/a:centos:centos:trustee-guest-components, cpe:/o:canonical:ubuntu_linux:18.04:-:lts, p-cpe:/a:redhat:enterprise_linux:s390utils-ziomon, p-cpe:/a:redhat:enterprise_linux:curl, p-cpe:/a:centos:centos:rust-src, p-cpe:/a:centos:centos:rust-std-static-aarch64-unknown-none-softfloat, cpe:/o:redhat:enterprise_linux:8, cpe:/o:debian:debian_linux:13.0, p-cpe:/a:centos:centos:rust-analyzer, p-cpe:/a:redhat:enterprise_linux:s390utils-se-data, p-cpe:/a:redhat:enterprise_linux:rust-std-static-aarch64-unknown-none-softfloat, p-cpe:/a:centos:centos:s390utils-hmcdrvfs, cpe:/o:centos:centos:7, p-cpe:/a:redhat:enterprise_linux:rust-std-static-wasm32-unknown-unknown, p-cpe:/a:canonical:ubuntu_linux:curl, p-cpe:/a:centos:centos:s390utils-se-data, p-cpe:/a:redhat:enterprise_linux:curl-minimal, p-cpe:/a:centos:centos:s390utils-base, p-cpe:/a:redhat:enterprise_linux:s390utils-devel, p-cpe:/a:redhat:enterprise_linux:rust-debugger-common, p-cpe:/a:centos:centos:s390utils-core, p-cpe:/a:redhat:enterprise_linux:snphost, p-cpe:/a:redhat:enterprise_linux:s390utils-iucvterm, p-cpe:/a:centos:centos:rust-gdb, p-cpe:/a:centos:centos:s390utils-zdsfs, p-cpe:/a:redhat:enterprise_linux:rust-std-static, p-cpe:/a:redhat:enterprise_linux:s390utils-hmcdrvfs, p-cpe:/a:centos:centos:rust-toolset, p-cpe:/a:centos:centos:rust, cpe:/o:debian:debian_linux:12.0, p-cpe:/a:redhat:enterprise_linux:s390utils-chreipl-fcp-mpath, p-cpe:/a:centos:centos:s390utils, cpe:/o:centos:centos:8, p-cpe:/a:centos:centos:rust-std-static, p-cpe:/a:centos:centos:s390utils-iucvterm, p-cpe:/a:debian:debian_linux:curl, p-cpe:/a:redhat:enterprise_linux:trustee, p-cpe:/a:centos:centos:libcurl-minimal, p-cpe:/a:centos:centos:rust-lldb, p-cpe:/a:centos:centos:s390utils-ziomon, p-cpe:/a:redhat:enterprise_linux:rust-doc, p-cpe:/a:centos:centos:rust-std-static-wasm32-wasi, p-cpe:/a:centos:centos:curl, p-cpe:/a:redhat:enterprise_linux:s390utils-osasnmpd, p-cpe:/a:centos:centos:s390utils-chreipl-fcp-mpath, p-cpe:/a:redhat:enterprise_linux:s390utils-cpacfstatsd, p-cpe:/a:centos:centos:curl-minimal

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

Exploit Available: true

Exploit Ease: Exploits are available

Reference Information

CVE: CVE-2026-6253