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CVE-2026-116566VulnerabilityPublished Updated

Red Hat Security Advisory: Red Hat Hardened Images RPMs Security Update

Affects Red HatSource GCVE Database

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Authoritative record:CVE-2026-116566· Medium 5.3

Not known to be exploited · CVSS 5.3 Medium : upgrade Red Hat CPython to 3.16.0 when convenient.

Data as of 13 Nov 2026, 05:28 UTC

CVSS 4.0 base score
5.3Medium
How severe the flaw is on the 0–10 CVSS scale.

Thin evidence

One scorer or none
CVSS scores by source
CNA (PSF)CVSS 4.05.3
Patch
Available – fixed in 3.16.0
CVSS:4.0/AV:A/AC:L/AT:P/PR:H/UI:P/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 29 Oct 2026

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponized: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq Mirage: no evidence on record.

    No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 13 Nov 2026.

What to do

Upgrade CPython to 3.16.0.

Affected software

ProductAffectedFixed in
Python Software FoundationCPythonAffected
  • <3.16.0
Fixed in
  • 3.16.0
GitHubCPythonpkg:github/CPythonOther threatsAffected
  • <3.16.0
Fixed in
  • 3.16.0

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

AI-suggested

Apply the Red Hat update for python3.13 packages as provided in the advisory. Alternatively, reject or sanitize null byte characters in host and port parameters before calling socket.getaddrinfo(). Upgrading to CPython 3.16.0 or a build carrying the backported fix also mitigates this vulnerability.

Description

A vulnerability in Python's socket.getaddrinfo() function allows an attacker to bypass security controls by using null byte characters in host or port parameters, causing silent truncation during address resolution. This can enable evasion of validation filters such as domain or port allowlists. The issue affects Red Hat Hardened Images RPMs for python3.13 and related packages. Red Hat rates this vulnerability as moderate impact because exploitation requires forwarding unsanitized external input to hostname resolution routines relying on prefix or suffix validation. The vulnerability does not directly compromise system integrity or allow remote code execution. A fix is available in Python 3.16.0 and backported builds.

References

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