CVE-2026-19553 Affecting python3-debug package, versions <0:3.12.15-1.el10_2


Severity

Recommended
high

Based on AlmaLinux security rating.

Threat Intelligence

EPSS
0.4% (33rd percentile)

Do your applications use this vulnerable package?

In a few clicks we can analyze your entire application and see what components are vulnerable in your application, and suggest you quick fixes.

Test your applications
  • Snyk IDSNYK-ALMALINUX10-PYTHON3DEBUG-20727653
  • published10 Oct 2026
  • disclosed6 Oct 2026

Introduced: 6 Oct 2026

NewCVE-2026-19553  (opens in a new tab)

How to fix?

Upgrade AlmaLinux:10 python3-debug to version 0:3.12.15-1.el10_2 or higher.
This issue was patched in ALSA-2026:77020.

NVD Description

Note: Versions mentioned in the description apply only to the upstream python3-debug package and not the python3-debug package as distributed by AlmaLinux. See How to fix? for AlmaLinux:10 relevant fixed versions and status.

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.

CVSS Base Scores

version 3.1