Debian dla-4827 : idle-python3.11 - security update

critical Nessus Plugin ID 364182

Synopsis

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

Description

The remote Debian 12 host has packages installed that are affected by multiple vulnerabilities as referenced in the dla-4827 advisory.

- ------------------------------------------------------------------------- Debian LTS Advisory DLA-4827-1 [email protected] https://www.debian.org/lts/security/ Andrej Shadura October 08, 2026 https://wiki.debian.org/LTS
- -------------------------------------------------------------------------

Package : python3.11 Version : 3.11.2-6+deb12u9 CVE ID : CVE-2025-69534 CVE-2026-1502 CVE-2026-3276 CVE-2026-6019 CVE-2026-8328 CVE-2026-9669 CVE-2026-15308 CVE-2026-15310 CVE-2026-15806 CVE-2026-17084 CVE-2026-18503 CVE-2026-19445 CVE-2026-19553 Debian Bug : 1131896

Multiple vulnerabilities in Python 3.11.

CVE-2025-69534

Malformed markup declarations could make html.parser.HTMLParser raise an unhandled AssertionError. Applications parsing untrusted HTML, such as Python-Markdown rendering untrusted input, could crash, resulting in denial of service.

CVE-2026-1502

http.client did not reject CR/LF bytes in the proxy tunnel host or in tunnel request headers, which could allow HTTP header injection.

CVE-2026-3276

unicodedata.normalize() could take excessive CPU time when processing specially crafted Unicode input containing long runs of combining characters with alternating canonical combining class values. This affected all normalization forms.

CVE-2026-6019

http.cookies.Morsel.js_output() returned an inline <script> snippet in which the cookie value was only escaped for the JavaScript string context, without neutralising the </script> sequence, so attacker-controlled cookie values could inject markup into the page.

CVE-2026-8328

ftplib.ftpcp() was not updated when CVE-2021-4189 was fixed and still passed the address returned by the source server for PASV to the target server. A malicious source FTP server could use this to direct the target server's data connection to an arbitrary host and port.

CVE-2026-9669

bz2.BZ2Decompressor objects could be reused after a decompression error. If an application caught the resulting OSError and retried with the same decompressor, crafted input could cause out-of-bounds writes to a stack buffer, crashing the process.

CVE-2026-15308

Feeding html.parser.HTMLParser incrementally with long unterminated constructs, such as tags or comments, took quadratic time, allowing denial of service through CPU exhaustion.

CVE-2026-15310

When decompressing crafted zip files using bzip2 or LZMA compression, zipfile could use an attacker-controlled size to pre-allocate memory, possibly resulting in memory exhaustion.

CVE-2026-15806

urllib.request.HTTPPasswordMgr and its subclasses did not take the URL scheme into account when matching stored credentials.
Credentials added for an https:// URL were also sent to the same host over http://, so an attacker able to redirect or downgrade a client to plain HTTP could capture them in cleartext.

CVE-2026-17084

The stringprep module used current Unicode codepoint attributes instead of those of Unicode 3.2.0, as required by RFC 3454, when checking tables B.2 and B.3. This could cause mismatches when processing domain names with the IDNA 2003 (idna) codec.

CVE-2026-18503

Attacker-controlled CSV samples could trigger super-linear regular expression matching in csv.Sniffer.sniff(), consuming significant CPU time.

CVE-2026-19445

A remote, unauthenticated TLS client could make a server crash or call through a freed pointer if the server's sni_callback assigned a different context to SSLSocket.context and nothing else kept the original ssl.SSLContext alive.

CVE-2026-19553

ssl.SSLContext.wrap_bio() did not require the server_hostname argument when check_hostname was enabled, so hostname verification could be silently skipped; asyncio's create_connection() and loop.start_tls() were affected as well. For compatibility, Python 3.11 now emits a DeprecationWarning in this case instead of raising ValueError, so applications still need to pass a valid server_hostname.

For Debian 12 bookworm, these problems have been fixed in version 3.11.2-6+deb12u9.

In addition, this update includes the following related upstream fixes:

* csv.Sniffer.sniff() could take exponential time on samples with many quote characters while detecting doubled quotes (gh-109638).

* Regular expressions with possessive quantifiers could give wrong matches when the repeated sub-pattern contained backtracking (gh-100061, gh-106052).

* html.parser.HTMLParser did not parse start and end tags according to the HTML5 standard, and could lose data after an unclosed script or style tag (gh-135661, gh-86155). As a result of the fix, some malformed markup is parsed differently; for example, </ script> no longer ends a script element.

We recommend that you upgrade your python3.11 packages.

For the detailed security status of python3.11 please refer to its security tracker page at:
https://security-tracker.debian.org/tracker/python3.11

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-python3.11 packages.

Plugin Details

Severity: Critical

ID: 364182

File Name: debian_DLA-4827.nasl

Version: 1.1

Type: Local

Agent: unix

Family: Debian Local Security Checks

Published: 10/8/2026

Updated: 10/8/2026

Supported Sensors: Nessus Agent, Continuous Assessment, Nessus

Risk Information

VPR

Risk Factor: Medium

Score: 6.3

Percentile: 96.3

CVSS v2

Risk Factor: Medium

Base Score: 6.4

Temporal Score: 5

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

CVSS Score Source: CVE-2026-6019

CVSS v3

Risk Factor: Medium

Base Score: 6.1

Temporal Score: 5.5

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

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

CVSS v4

Risk Factor: Critical

Base Score: 9.2

Threat Score: 8.1

Threat Vector: CVSS:4.0/E:P

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

CVSS Score Source: CVE-2026-19445

Vulnerability Information

CPE: cpe:/o:debian:debian_linux:12.0, p-cpe:/a:debian:debian_linux:idle-python3.11, p-cpe:/a:debian:debian_linux:libpython3.11-dbg, p-cpe:/a:debian:debian_linux:libpython3.11-dev, p-cpe:/a:debian:debian_linux:libpython3.11-minimal, p-cpe:/a:debian:debian_linux:libpython3.11-stdlib, p-cpe:/a:debian:debian_linux:libpython3.11-testsuite, p-cpe:/a:debian:debian_linux:libpython3.11, p-cpe:/a:debian:debian_linux:python3.11-dbg, p-cpe:/a:debian:debian_linux:python3.11-dev, p-cpe:/a:debian:debian_linux:python3.11-doc, p-cpe:/a:debian:debian_linux:python3.11-examples, p-cpe:/a:debian:debian_linux:python3.11-full, p-cpe:/a:debian:debian_linux:python3.11-minimal, p-cpe:/a:debian:debian_linux:python3.11-nopie, p-cpe:/a:debian:debian_linux:python3.11-venv, p-cpe:/a:debian:debian_linux:python3.11

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

Exploit Available: true

Exploit Ease: Exploits are available

Patch Publication Date: 10/8/2026

Vulnerability Publication Date: 8/24/2021

Reference Information

CVE: CVE-2021-4189, CVE-2025-69534, CVE-2026-1502, CVE-2026-15308, CVE-2026-15310, CVE-2026-15806, CVE-2026-17084, CVE-2026-18503, CVE-2026-19445, CVE-2026-19553, CVE-2026-3276, CVE-2026-6019, CVE-2026-8328, CVE-2026-9669

Detections

Analytics

Debian dla-4827 : idle-python3.11 - security update

critical Nessus Plugin ID 364182

Synopsis

Description

Solution

See Also

Plugin Details

Risk Information

VPR

CVSS v2

CVSS v3

CVSS v4

Vulnerability Information

Reference Information