Detections
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Ubuntu 18.04 LTS / 20.04 LTS / 22.04 LTS / 24.04 LTS / 26.04 LTS : phpseclib vulnerabilities (USN-8830-1)

high Nessus Plugin ID 350947

Synopsis

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

Description

The remote Ubuntu 18.04 LTS / 20.04 LTS / 22.04 LTS / 24.04 LTS / 26.04 LTS host has a package installed that is affected by multiple vulnerabilities as referenced in the USN-8830-1 advisory.

 It was discovered that phpseclib did not perform constant-time padding validation when using AES in CBC mode. A remote attacker could possibly use this issue to obtain sensitive information. (CVE-2026-32935)

 It was discovered that phpseclib did not use a constant-time comparison when validating SSH packet authentication codes. A remote attacker could possibly use this issue to obtain sensitive information.
 (CVE-2026-40194)

 It was discovered that phpseclib did not properly limit object identifier lengths when parsing ASN.1 data.
 An attacker could possibly use this issue to cause phpseclib to use excessive resources, leading to a denial of service. (CVE-2026-44167)

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 php-phpseclib package.

See Also

https://ubuntu.com/security/notices/USN-8830-1

Plugin Details

Severity: High

ID: 350947

File Name: ubuntu_USN-8830-1.nasl

Version: 1.2

Type: Local

Agent: unix

Published: 9/29/2026

Updated: 9/29/2026

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

Risk Information

VPR

Risk Factor: Low

Score: 3

Percentile: 23.75

CVSS v2

Risk Factor: Medium

Base Score: 5.4

Temporal Score: 4

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

CVSS Score Source: CVE-2026-32935

CVSS v3

Risk Factor: Medium

Base Score: 5.9

Temporal Score: 5.2

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

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

CVSS v4

Risk Factor: High

Base Score: 8.2

Threat Score: 4.6

Threat Vector: CVSS:4.0/E:U

Vector: CVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N

Vulnerability Information

CPE: cpe:/o:canonical:ubuntu_linux:18.04:-:lts, cpe:/o:canonical:ubuntu_linux:20.04:-:lts, cpe:/o:canonical:ubuntu_linux:22.04:-:lts, cpe:/o:canonical:ubuntu_linux:24.04:-:lts, cpe:/o:canonical:ubuntu_linux:26.04:-:lts, p-cpe:/a:canonical:ubuntu_linux:php-phpseclib

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

Exploit Ease: No known exploits are available

Patch Publication Date: 9/28/2026

Vulnerability Publication Date: 3/19/2026

Reference Information

CVE: CVE-2026-32935, CVE-2026-40194, CVE-2026-44167

USN: 8830-1