Detections
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Ubuntu 14.04 LTS / 16.04 LTS / 18.04 LTS / 20.04 LTS : pyasn1 vulnerabilities (USN-8134-1)

high Nessus Plugin ID 304433

Synopsis

The remote Ubuntu host is missing one or more security updates.

Description

The remote Ubuntu 14.04 LTS / 16.04 LTS / 18.04 LTS / 20.04 LTS host has packages installed that are affected by multiple vulnerabilities as referenced in the USN-8134-1 advisory.

 It was discovered that pyasn1 could exhaust system resources when attempting to decode a malformed certificate. An attacker could possibly use this to cause a denial of service. (CVE-2026-23490)

 Kevin Tu discovered that pyasn1 could exhaust system resources via uncontrolled recursion when attempting to decode malicously-crafted certificates. An attacker could possibly use this to cause a denial of service. (CVE-2026-30922)

Tenable has extracted the preceding description block directly from the Ubuntu security advisory.

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

Solution

Update the affected pypy-pyasn1, python-pyasn1 and / or python3-pyasn1 packages.

See Also

https://ubuntu.com/security/notices/USN-8134-1

Plugin Details

Severity: High

ID: 304433

File Name: ubuntu_USN-8134-1.nasl

Version: 1.1

Type: local

Agent: unix

Published: 3/31/2026

Updated: 3/31/2026

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

Risk Information

VPR

Risk Factor: Medium

Score: 4.4

CVSS v2

Risk Factor: High

Base Score: 7.8

Temporal Score: 6.1

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

CVSS Score Source: CVE-2026-30922

CVSS v3

Risk Factor: High

Base Score: 7.5

Temporal Score: 6.7

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

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

Vulnerability Information

CPE: cpe:/o:canonical:ubuntu_linux:14.04:-:lts, cpe:/o:canonical:ubuntu_linux:20.04:-:lts, cpe:/o:canonical:ubuntu_linux:16.04:-:lts, cpe:/o:canonical:ubuntu_linux:18.04:-:lts, p-cpe:/a:canonical:ubuntu_linux:pypy-pyasn1, p-cpe:/a:canonical:ubuntu_linux:python-pyasn1, p-cpe:/a:canonical:ubuntu_linux:python3-pyasn1

Required KB Items: Host/cpu, Host/Debian/dpkg-l, Host/Ubuntu, Host/Ubuntu/release

Exploit Available: true

Exploit Ease: Exploits are available

Patch Publication Date: 3/30/2026

Vulnerability Publication Date: 1/16/2026

Reference Information

CVE: CVE-2026-23490, CVE-2026-30922

USN: 8134-1