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Debian dla-4455 : idle-python3.9 - security update

medium Nessus Plugin ID 296553

Synopsis

The remote Debian host is missing one or more security-related updates.

Description

The remote Debian 11 host has packages installed that are affected by multiple vulnerabilities as referenced in the dla-4455 advisory.

 - ------------------------------------------------------------------------- Debian LTS Advisory DLA-4455-1 [email protected] https://www.debian.org/lts/security/ Andrej Shadura January 25, 2026 https://wiki.debian.org/LTS
 - -------------------------------------------------------------------------

 Package : python3.9 Version : 3.9.2-1+deb11u5 CVE ID : CVE-2025-11468 CVE-2025-12084 CVE-2025-15282 CVE-2025-15366 CVE-2025-15367 CVE-2026-0672 CVE-2026-0865 CVE-2026-1299

 This upload fixes a regression introduced in 3.9.2-1+deb11u4 (DLA 4445-1), and also fixes multiple security issues in cPython 3.9.

 CVE-2025-12084

 When building nested elements using xml.dom.minidom methods such as appendChild() that have a dependency on _clear_id_cache() the algorithm was quadratic. Availability could be impacted when building excessively nested documents.

 The fix for this CVE in the previous upload resulted in a regression in software relying on ownerDocument attribute being always present in Element instances. This regression has now been fixed.

 CVE-2026-0672, CVE-2026-0865, CVE-2025-15282, CVE-2025-15366, CVE-2025-15367

 These are all similar vulnerabilities in the following modules:
 http.cookies, wsgiref.headers, imaplib, poplib, urllib. In each of these control characters were handled incorrectly, allowing injection of additional cookiers, headers or commands. Control characters are now rejected in these contexts.

 CVE-2025-11468

 An issue similar to the above. Comments consisting of a very long sequence of non-foldable characters could trigger a forced line wrap that omitted the required leading space on the continuation line, causing the remainder of the comment to be interpreted as a new header field.

 CVE-2026-1299

 Another header injection issue: email module allowed header injection in the BytesGenerator class. BytesGenerator will now refuse to serialize headers that are unsafely folded or delimited.

 For Debian 11 bullseye, these problems have been fixed in version 3.9.2-1+deb11u5.

 We recommend that you upgrade your python3.9 packages.

 For the detailed security status of python3.9 please refer to its security tracker page at:
 https://security-tracker.debian.org/tracker/python3.9

 Further information about Debian LTS security advisories, how to apply these updates to your system and frequently asked questions can be found at: https://wiki.debian.org/LTS

Tenable has extracted the preceding description block directly from the Debian 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

Upgrade the idle-python3.9 packages.

See Also

https://security-tracker.debian.org/tracker/source-package/python3.9

https://security-tracker.debian.org/tracker/CVE-2025-11468

https://security-tracker.debian.org/tracker/CVE-2025-12084

https://security-tracker.debian.org/tracker/CVE-2025-15282

https://security-tracker.debian.org/tracker/CVE-2025-15366

https://security-tracker.debian.org/tracker/CVE-2025-15367

https://security-tracker.debian.org/tracker/CVE-2026-0672

https://security-tracker.debian.org/tracker/CVE-2026-0865

https://security-tracker.debian.org/tracker/CVE-2026-1299

https://packages.debian.org/source/bullseye/python3.9

Plugin Details

Severity: Medium

ID: 296553

File Name: debian_DLA-4455.nasl

Version: 1.1

Type: local

Agent: unix

Published: 1/25/2026

Updated: 1/25/2026

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

Risk Information

VPR

Risk Factor: High

Score: 7.4

CVSS v2

Risk Factor: Medium

Base Score: 5

Temporal Score: 3.7

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

CVSS Score Source: CVE-2025-12084

CVSS v3

Risk Factor: Medium

Base Score: 5.3

Temporal Score: 4.6

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

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

CVSS v4

Risk Factor: Medium

Base Score: 6.3

Threat Score: 1.7

Threat Vector: CVSS:4.0/E:U

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

Vulnerability Information

CPE: p-cpe:/a:debian:debian_linux:idle-python3.9, p-cpe:/a:debian:debian_linux:libpython3.9-minimal, p-cpe:/a:debian:debian_linux:libpython3.9-dbg, cpe:/o:debian:debian_linux:11.0, p-cpe:/a:debian:debian_linux:python3.9, p-cpe:/a:debian:debian_linux:libpython3.9-dev, p-cpe:/a:debian:debian_linux:python3.9-minimal, p-cpe:/a:debian:debian_linux:python3.9-dbg, p-cpe:/a:debian:debian_linux:libpython3.9-testsuite, p-cpe:/a:debian:debian_linux:libpython3.9, p-cpe:/a:debian:debian_linux:python3.9-venv, p-cpe:/a:debian:debian_linux:python3.9-dev, p-cpe:/a:debian:debian_linux:libpython3.9-stdlib, p-cpe:/a:debian:debian_linux:python3.9-full, p-cpe:/a:debian:debian_linux:python3.9-examples, p-cpe:/a:debian:debian_linux:python3.9-doc

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

Exploit Ease: No known exploits are available

Patch Publication Date: 1/25/2026

Vulnerability Publication Date: 12/3/2025

Reference Information

CVE: CVE-2025-11468, CVE-2025-12084, CVE-2025-15282, CVE-2025-15366, CVE-2025-15367, CVE-2026-0672, CVE-2026-0865, CVE-2026-1299