Linux Distros Unpatched Vulnerability : CVE-2026-50722

medium Nessus Plugin ID 324998

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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.

- Libreswan, via the function RSA_authenticate_hash_signature_pkcs1_1_5_rsa(), did not correctly verify the DER encoding of the ASN.1 digest when the IKEv2 AUTH payload was encoded using RSASSA-PKCS1-v1_5 (RFC 8017). A remote attacker can use a variation on the Bleichenbacher attack to forge the AUTH payload when small public exponents are used (e.g., e=3), leading to impersonation. Additionally, a remote attacker, by encoding a shorter than expected hash in the AUTH payload, could trigger an assertion leading to denial- of-service. The daemon aborts and restarts; continued exploitation causes sustained denial of service.
Remote code execution is not possible. X.509 certificate verifications of the remote IKE peer are not affected. (CVE-2026-50722)

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: 324998

File Name: unpatched_CVE_2026_50722.nasl

Version: 1.5

Type: Local

Agent: unix

Family: Misc.

Published: 7/3/2026

Updated: 7/15/2026

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: Low

Score: 3

Percentile: 23.8

CVSS v2

Risk Factor: Medium

Base Score: 5.4

Temporal Score: 4.6

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

CVSS Score Source: CVE-2026-50722

CVSS v3

Risk Factor: Medium

Base Score: 5.9

Temporal Score: 5.4

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:U/RL:U/RC:C

Vulnerability Information

CPE: cpe:/o:debian:debian_linux:11.0, cpe:/o:canonical:ubuntu_linux:20.04:-:lts, p-cpe:/a:debian:debian_linux:libreswan, cpe:/o:canonical:ubuntu_linux:24.04:-:lts, p-cpe:/a:redhat:enterprise_linux:libreswan-minimal, p-cpe:/a:redhat:enterprise_linux:libreswan, cpe:/o:debian:debian_linux:12.0, cpe:/o:canonical:ubuntu_linux:25.10, cpe:/o:redhat:enterprise_linux:9, cpe:/o:canonical:ubuntu_linux:18.04:-:lts, cpe:/o:centos:centos:8, cpe:/o:redhat:enterprise_linux:8, cpe:/o:debian:debian_linux:13.0, cpe:/o:redhat:enterprise_linux:10, p-cpe:/a:centos:centos:libreswan, p-cpe:/a:canonical:ubuntu_linux:libreswan, cpe:/o:canonical:ubuntu_linux:26.04:-:lts, cpe:/o:centos:centos:7, cpe:/o:redhat:enterprise_linux:7, cpe:/o:canonical:ubuntu_linux:22.04:-:lts, cpe:/o:debian:debian_linux:14.0, p-cpe:/a:centos:centos:libreswan-minimal

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

Exploit Ease: No known exploits are available

Vulnerability Publication Date: 7/2/2026

Reference Information

CVE: CVE-2026-50722

Detections

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