Linux Distros Unpatched Vulnerability : CVE-2026-48523

medium Nessus Plugin ID 317757

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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.

- PyJWT is a JSON Web Token implementation in Python. From 2.9.0 to 2.12.1, there is a verifier-side algorithm allow-list bypass when jwt.decode() or jwt.decode_complete() are called with a PyJWK key. The token header alg is checked against the caller-supplied algorithms allow-list, but signature verification is performed with the algorithm bound to the PyJWK object instead of the header algorithm. An attacker who controls a registered JWK/JWKS private key can sign with a disallowed algorithm, advertise an allowed algorithm in the JWT header, and still be accepted. The issue affects the documented PyJWKClient.get_signing_key_from_jwt(...) flow. This vulnerability is fixed in 2.13.0. (CVE-2026-48523)

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

Solution

There is no known solution at this time.

Plugin Details

Severity: Medium

ID: 317757

File Name: unpatched_CVE_2026_48523.nasl

Version: 1.4

Type: Local

Agent: unix

Family: Misc.

Published: 5/29/2026

Updated: 6/5/2026

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

Risk Information

VPR

Risk Factor: Low

Score: 3.3

CVSS v2

Risk Factor: Medium

Base Score: 6.4

Temporal Score: 5.8

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

CVSS Score Source: CVE-2026-48523

CVSS v3

Risk Factor: Medium

Base Score: 5.4

Temporal Score: 5.1

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

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

Vulnerability Information

CPE: cpe:/o:debian:debian_linux:11.0, cpe:/o:canonical:ubuntu_linux:20.04:-:lts, cpe:/o:canonical:ubuntu_linux:24.04:-:lts, p-cpe:/a:redhat:enterprise_linux:fence-agents-cisco-ucs, p-cpe:/a:redhat:enterprise_linux:fence-agents-drac5, p-cpe:/a:redhat:enterprise_linux:fence-agents-bladecenter, p-cpe:/a:redhat:enterprise_linux:fence-agents-ilo-ssh, p-cpe:/a:redhat:enterprise_linux:fence-agents, p-cpe:/a:redhat:enterprise_linux:fence-agents-wti, p-cpe:/a:redhat:enterprise_linux:fence-agents-compute, p-cpe:/a:redhat:enterprise_linux:fence-agents-rsb, p-cpe:/a:redhat:enterprise_linux:fence-agents-scsi, p-cpe:/a:redhat:enterprise_linux:fence-agents-ipmilan, p-cpe:/a:redhat:enterprise_linux:fence-agents-eaton-snmp, p-cpe:/a:redhat:enterprise_linux:fence-agents-openstack, cpe:/o:debian:debian_linux:12.0, p-cpe:/a:redhat:enterprise_linux:fence-agents-ilo2, cpe:/o:canonical:ubuntu_linux:25.10, p-cpe:/a:redhat:enterprise_linux:fence-agents-ilo-moonshot, p-cpe:/a:redhat:enterprise_linux:fence-agents-intelmodular, cpe:/o:redhat:enterprise_linux:9, p-cpe:/a:debian:debian_linux:pyjwt, cpe:/o:canonical:ubuntu_linux:18.04:-:lts, p-cpe:/a:redhat:enterprise_linux:fence-agents-ibmblade, p-cpe:/a:redhat:enterprise_linux:fence-agents-kdump, p-cpe:/a:redhat:enterprise_linux:fence-virt, p-cpe:/a:redhat:enterprise_linux:fence-virtd-cpg, p-cpe:/a:redhat:enterprise_linux:fence-virtd-multicast, p-cpe:/a:redhat:enterprise_linux:fence-agents-ibm-vpc, p-cpe:/a:redhat:enterprise_linux:fence-agents-eps, p-cpe:/a:redhat:enterprise_linux:fence-agents-kubevirt, p-cpe:/a:redhat:enterprise_linux:fence-agents-ipdu, p-cpe:/a:redhat:enterprise_linux:fence-agents-nutanix-ahv, p-cpe:/a:redhat:enterprise_linux:fence-agents-emerson, p-cpe:/a:redhat:enterprise_linux:fence-agents-all, cpe:/o:debian:debian_linux:13.0, cpe:/o:redhat:enterprise_linux:10, p-cpe:/a:redhat:enterprise_linux:fence-agents-apc-snmp, p-cpe:/a:redhat:enterprise_linux:fence-agents-zvm, p-cpe:/a:redhat:enterprise_linux:fence-agents-rhevm, p-cpe:/a:redhat:enterprise_linux:fence-agents-ifmib, p-cpe:/a:redhat:enterprise_linux:fence-agents-mpath, p-cpe:/a:redhat:enterprise_linux:fence-agents-aws, p-cpe:/a:redhat:enterprise_linux:fence-agents-gce, p-cpe:/a:redhat:enterprise_linux:fence-agents-virsh, p-cpe:/a:redhat:enterprise_linux:fence-virtd-serial, p-cpe:/a:redhat:enterprise_linux:fence-agents-redfish, p-cpe:/a:redhat:enterprise_linux:fence-agents-amt-ws, p-cpe:/a:redhat:enterprise_linux:fence-agents-brocade, p-cpe:/a:redhat:enterprise_linux:fence-virtd-tcp, cpe:/o:canonical:ubuntu_linux:26.04:-:lts, p-cpe:/a:redhat:enterprise_linux:fence-agents-lpar, p-cpe:/a:redhat:enterprise_linux:fence-agents-vmware-rest, p-cpe:/a:redhat:enterprise_linux:fence-virtd, p-cpe:/a:redhat:enterprise_linux:fence-agents-azure-arm, cpe:/o:canonical:ubuntu_linux:16.04:-:lts, p-cpe:/a:redhat:enterprise_linux:fence-agents-hpblade, p-cpe:/a:redhat:enterprise_linux:fence-agents-ilo-mp, p-cpe:/a:redhat:enterprise_linux:fence-agents-aliyun, p-cpe:/a:redhat:enterprise_linux:fence-virtd-libvirt, p-cpe:/a:redhat:enterprise_linux:fence-agents-vmware-soap, p-cpe:/a:redhat:enterprise_linux:fence-agents-common, p-cpe:/a:canonical:ubuntu_linux:pyjwt, p-cpe:/a:redhat:enterprise_linux:fence-agents-apc, cpe:/o:canonical:ubuntu_linux:22.04:-:lts, cpe:/o:debian:debian_linux:14.0, p-cpe:/a:redhat:enterprise_linux:fence-agents-heuristics-ping, p-cpe:/a:redhat:enterprise_linux:fence-agents-ibm-powervs, p-cpe:/a:redhat:enterprise_linux:fence-agents-sbd, p-cpe:/a:redhat:enterprise_linux:fence-agents-cisco-mds, p-cpe:/a:redhat:enterprise_linux:fence-agents-rsa, p-cpe:/a:redhat:enterprise_linux:ha-cloud-support

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

Exploit Available: true

Exploit Ease: Exploits are available

Vulnerability Publication Date: 5/28/2026

Reference Information

CVE: CVE-2026-48523

Detections

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