Detections
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Ubuntu 18.04 LTS / 26.04 LTS : python-cryptography vulnerabilities (USN-8776-1)

high Nessus Plugin ID 346812

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Synopsis

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

Description

The remote Ubuntu 18.04 LTS / 26.04 LTS host has packages installed that are affected by multiple vulnerabilities as referenced in the USN-8776-1 advisory.

 It was discovered that python-cryptography incorrectly accepted objects with immutable buffers when performing certain cipher operations. This would result in corrupted output, contrary to expectations.
 This issue only affected Ubuntu 18.04 LTS. (CVE-2023-23931)

 It was discovered that python-cryptography reported the outcome of decrypting PKCS#7 enveloped data in distinguishable ways, and with observable timing differences. A remote attacker could possibly use this issue to recover the key used to encrypt the message contents, and obtain sensitive information. This issue only affected Ubuntu 26.04 LTS. (CVE-2026-69247)

 Jack Lloyd discovered that python-cryptography incorrectly handled wildcard DNS names when enforcing the name constraints of a certificate authority. A remote attacker could possibly use this issue to have an invalid certificate chain accepted, and use names outside of the permitted ones. This issue only affected Ubuntu 26.04 LTS. (CVE-2026-69248)

 Samuel Judson discovered that python-cryptography incorrectly handled certificate chains that contained duplicate certificates. A remote attacker could possibly use this issue to cause python-cryptography to use excessive resources, leading to a denial of service. This issue only affected Ubuntu 26.04 LTS.
 (CVE-2026-69249)

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 python-cryptography and / or python3-cryptography packages.

See Also

https://ubuntu.com/security/notices/USN-8776-1

Plugin Details

Severity: High

ID: 346812

File Name: ubuntu_USN-8776-1.nasl

Version: 1.3

Type: Local

Agent: unix

Published: 9/17/2026

Updated: 9/25/2026

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: Medium

Score: 4.3

Percentile: 53.44

CVSS v2

Risk Factor: Medium

Base Score: 6.4

Temporal Score: 5

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

CVSS Score Source: CVE-2023-23931

CVSS v3

Risk Factor: Medium

Base Score: 6.5

Temporal Score: 5.9

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

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

CVSS v4

Risk Factor: High

Base Score: 8.7

Threat Score: 7.7

Threat Vector: CVSS:4.0/E:P

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

CVSS Score Source: CVE-2026-69249

Vulnerability Information

CPE: cpe:/o:canonical:ubuntu_linux:18.04:-:lts, cpe:/o:canonical:ubuntu_linux:26.04:-:lts, p-cpe:/a:canonical:ubuntu_linux:python-cryptography, p-cpe:/a:canonical:ubuntu_linux:python3-cryptography

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: 9/16/2026

Vulnerability Publication Date: 9/16/2026

Reference Information

CVE: CVE-2023-23931, CVE-2026-69247, CVE-2026-69248, CVE-2026-69249

USN: 8776-1