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Alibaba Cloud Linux 3 : 0348: python3 (ALINUX3-SA-2026:0348)
critical Nessus Plugin ID 379727
Synopsis
The remote Alibaba Cloud Linux host is missing one or more security updates.Description
The remote Alibaba Cloud Linux 3 host has packages installed that are affected by multiple vulnerabilities as referenced in the ALINUX3-SA-2026:0348 advisory.Package updates are available for Alibaba Cloud Linux 3 that fix the following vulnerabilities:
CVE-2026-12345:
The cleanup of tempfile.TemporaryDirectory is vulnerable to a race condition. An attacker who can modify the tree during cleanup can replace a directory with a symbolic link, causing files outside of the temporary directory to be deleted or have their permissions and file flags reset, with the privileges of the process performing the cleanup. Note that platforms where shutil.rmtree.avoids_symlink_attacks is false, remain affected, and file flags may still be reset outside of the tree on all platforms.
CVE-2026-19445:
A remote, unauthenticated TLS client can make a server crash or call through a freed pointer if its sni_callback assigns a different context to SSLSocket.context (the documented way to select a certificate per server name) and nothing else keeps the original ssl.SSLContext alive. Typical cases are servers that create an SSLContext per connection or replace it while connections are open; servers that wrap their listening socket with it are not affected.
Mitigation: keep a reference to every SSLContext that sets sni_callback for the lifetime of the server. TLS clients are not affected.
CVE-2026-19553:
ssl.SSLContext.wrap_bio() didn't require the server_hostname argument to not be None if ssl.SSLContext.check_hostname was set. Due to a missing parameter check in SSLObject, if the server_hostname argument isn't supplied then hostname verification would be silently skipped.
This defect could lead to programs where certificate hostname verification
*appeared* to be succeeding with SSLContext.check_hostname = True and no ValueError being raised due to misconfiguration.
If the program passes a server_hostname value that isn't an empty string or None to any of these APIs then certificate hostname verification proceeds as expected and the program is not affected by this vulnerability.
Mitigating this vulnerability doesn't require updating Python or applying the patch. To mitigate, pass a valid non-None and non-empty server_hostname value to SSLContext.wrap_bio(), asyncio.create_connection(), or asyncio.loop.start_tls() and certificate hostname verification will proceed as expected. Upgrading to the latest version of Python or applying the patch only changes the behavior from silently skipping hostname verification to raising a ValueError, similar to SSLContext.wrap_socket(), when server_hostname isn't supplied.
Tenable has extracted the preceding description block directly from the Alibaba Cloud Linux 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 packages.See Also
http://mirrors.aliyun.com/alinux/3/cve/alinux3-sa-20260348.xml
Plugin Details
Severity: Critical
ID: 379727
File Name: alinux3_sa_2026-0348.nasl
Version: 1.1
Type: Local
Published: 11/12/2026
Updated: 11/12/2026
Supported Sensors: Nessus
Risk Information
VPR
Risk Factor: High
Score: 7.1
Percentile: 98.06
CVSS v2
Risk Factor: High
Base Score: 7.6
Temporal Score: 6
Vector: CVSS2#AV:N/AC:H/Au:N/C:C/I:C/A:C
CVSS Score Source: CVE-2026-19445
CVSS v3
Risk Factor: High
Base Score: 8.1
Temporal Score: 7.3
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: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
Vulnerability Information
CPE: cpe:/o:alibabacloud:alibaba_cloud_linux_3, p-cpe:/a:alibabacloud:alibaba_cloud_linux_3:platform-python-debug, p-cpe:/a:alibabacloud:alibaba_cloud_linux_3:platform-python-devel, p-cpe:/a:alibabacloud:alibaba_cloud_linux_3:platform-python, p-cpe:/a:alibabacloud:alibaba_cloud_linux_3:python3-devel, p-cpe:/a:alibabacloud:alibaba_cloud_linux_3:python3-idle, p-cpe:/a:alibabacloud:alibaba_cloud_linux_3:python3-libs, p-cpe:/a:alibabacloud:alibaba_cloud_linux_3:python3-test, p-cpe:/a:alibabacloud:alibaba_cloud_linux_3:python3-tkinter
Required KB Items: Host/local_checks_enabled, Host/cpu, Host/Alibaba/release, Host/Alibaba/rpm-list
Exploit Available: true
Exploit Ease: Exploits are available
Patch Publication Date: 11/11/2026
Vulnerability Publication Date: 8/20/2026