Amazon Linux 2023 : python3.11, python3.11-devel, python3.11-idle (ALAS2023-2026-1620)

critical Nessus Plugin ID 311323

Synopsis

The remote Amazon Linux 2023 host is missing a security update.

Description

It is, therefore, affected by multiple vulnerabilities as referenced in the ALAS2023-2026-1620 advisory.

The fix for CVE-2026-0672, which rejected control characters in http.cookies.Morsel, was incomplete. The Morsel.update(), |= operator, and unpickling paths were not patched, allowing control characters to bypass input validation. Additionally, BaseCookie.js_output() lacked the output validation applied to BaseCookie.output(). (CVE-2026-3644)

When an Expat parser with a registered ElementDeclHandler parses an inlinedocument type definition containing a deeply nested content model a C stackoverflow occurs. (CVE-2026-4224)

Mitgation of CVE-2026-4519 was incomplete. If the URL contained %action the mitigation could be bypassed for certain browser types the webbrowser.open() API could have commands injected into the underlying shell. See CVE-2026-4519 for details. (CVE-2026-4786)

Use-after-free (UAF) was possible in the `lzma.LZMADecompressor`, `bz2.BZ2Decompressor`, and `gzip.GzipFile` when a memory allocation fails with a `MemoryError` and the decompression instance is re- used. This scenario can be triggered if the process is under memory pressure. The fix cleans up the dangling pointer in this specific error condition.

The vulnerability is only present if the program re-uses decompressor instances across multiple decompression calls even after a `MemoryError` is raised during decompression. Using the helper functions to one-shot decompress data such as `lzma.decompress()`, `bz2.decompress()`, `gzip.decompress()`, and `zlib.decompress()` are not affected as a new decompressor instance is used per call. If the decompressor instance is not re-used after an error condition, this usage is similarly not vulnerable. (CVE-2026-6100)

Tenable has extracted the preceding description block directly from the tested product 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

Run 'dnf update python3.11 --releasever 2023.11.20260427' or or 'dnf update --advisory ALAS2023-2026-1620 --releasever 2023.11.20260427' to update your system.

Plugin Details

Severity: Critical

ID: 311323

File Name: al2023_ALAS2023-2026-1620.nasl

Version: 1.1

Type: Local

Agent: unix

Family: Amazon Linux Local Security Checks

Published: 4/30/2026

Updated: 4/30/2026

Supported Sensors: Nessus Agent, Continuous Assessment, Nessus

Risk Information

VPR

Risk Factor: Medium

Score: 6.7

CVSS v2

Risk Factor: High

Base Score: 7.6

Temporal Score: 5.6

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

CVSS Score Source: CVE-2026-6100

CVSS v3

Risk Factor: High

Base Score: 8.1

Temporal Score: 7.1

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

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

CVSS v4

Risk Factor: Critical

Base Score: 9.1

Threat Score: 6.9

Threat Vector: CVSS:4.0/E:U

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

Vulnerability Information

CPE: p-cpe:/a:amazon:linux:python3.11-debugsource, p-cpe:/a:amazon:linux:python3.11-tkinter, p-cpe:/a:amazon:linux:python3.11-devel, p-cpe:/a:amazon:linux:python3.11-debug, p-cpe:/a:amazon:linux:python3.11-test, p-cpe:/a:amazon:linux:python3.11-libs, cpe:/o:amazon:linux:2023, p-cpe:/a:amazon:linux:python3.11, p-cpe:/a:amazon:linux:python3.11-idle, p-cpe:/a:amazon:linux:python3.11-debuginfo

Required KB Items: Host/local_checks_enabled, Host/AmazonLinux/release, Host/AmazonLinux/rpm-list

Exploit Ease: No known exploits are available

Patch Publication Date: 4/30/2026

Vulnerability Publication Date: 2/12/2026

Reference Information

CVE: CVE-2026-3644, CVE-2026-4224, CVE-2026-4786, CVE-2026-6100

IAVA: 2026-A-0142-S

Detections

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