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  4. CVE 2026 116566 socketgetaddrinfo accepts embedded null bytes in
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Back to active CVEs
Medium · CVSS 5.3CVE-2026-116566

socket.getaddrinfo() accepts embedded null bytes in host and portCVE-2026-116566

Answer in brief

CVE-2026-116566 records a Medium severity (CVSS 5.3) vulnerability in socket.getaddrinfo() accepts embedded null bytes in host and port. The current sources do not mark it as known exploited. The current feed maps Python Software Foundation/CPython (generic). Check affected ranges and fixed versions before updating.

Analysis pending evidence review

HOL Guard separates source facts from reviewed analysis. See the methodology.

Published Oct 29, 2026Updated Oct 29, 2026Source checked Oct 29, 2026First seen by HOL Oct 29, 2026Material review Oct 29, 2026
Upstream Advisory

Key facts

Risk
Medium · CVSS 5.3
Exploitation
Not marked as known exploited
Affected software
1 mapped package or product
Fix availability
Available

Why this deserves its current priority

CVSS is 5.3. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.

Analysis status

Analysis pending evidence review

Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.

Affected scope and exposure questions

The current feed maps Python Software Foundation/CPython (generic). Check affected ranges and fixed versions before updating.

Mapped affected packages and fixed versions
PackageAffected rangeFixed version
Python Software Foundation/CPythongeneric>=0 <3.16.03.16.0

Recommended response

  1. 1Check inventory. Check lockfiles and deployed manifests for Python Software Foundation/CPython.
  2. 2Review the reported fix. Update Python Software Foundation/CPython to 3.16.0 if you use the affected versions. Test the change in a non-production environment first.

Evidence timeline and material changes

  1. Published upstream

    Oct 29, 2026

    Evidence: source:cvelist:source_dates:source-dates:record

  2. Source modified

    Oct 29, 2026

    Evidence: source:cvelist:source_dates:source-dates:record

  3. First seen by HOL

    Oct 29, 2026

Sources and claim methodology

  • GitHub security advisorygithub.com
  • GitHub security advisorygithub.com
  • Source referencemail.python.org
Upstream source description

socket.getaddrinfo() previously accepted null bytes within *host* and *port* parameters which can cause the values to be silently truncated.

Quoted source text, attributed separately from HOL analysis.

Related CVEs

  • Botan: Python binding bcrypt APIs truncate passwords containing embedded NULsAlso CWE-158

Record context

Vulnerability class
Vulnerability
EPSS
Not reported
CWE IDs
CWE-158
Source
CVE List V5
Source checked
Oct 29, 2026
References
3 linked sources
Open source record