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Fencer Intel
medium 5.3

CVE-2026-116566 json

socket.getaddrinfo() accepts embedded null bytes in host and port

published 11d ago modified 10d ago also EUVD-2026-113279

cvss
5.3
version 4.0, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.3%
EPSS 0.3% chance of exploitation in 30 days, percentile 17%
public exploits
0
none known

Summary

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

Patch / fix

  • Python Software Foundation CPython 3.16.0

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Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2026-116566 updated cvss 5.3

python: python: Security bypass via null byte truncation in socket.getaddrinfo()

  • Red Hat Enterprise Linux 6 python, tkinter, python-libs, python-test, python-tools
    affected: workaround, no fix planned “Out of support scope”
  • Red Hat Enterprise Linux 7 python, python3, tkinter, python-libs, python-test, python-tools, +4 more Red Hat Enterprise Linux 8 scipy, python3, python36, python3.12, python-nose, python-wheel, +32 more Red Hat Enterprise Linux 9 python3, python3.9, python3.12, python3.14, python3-idle, python3-libs, +18 more Red Hat Enterprise Linux 10 python3.14 3.14.8-1.el10_2, python3.12 3.12.15-1.el10_2 Red Hat Enterprise Linux AI (RHEL AI) 3 rhelai3/bootc-cuda-rhel9, rhelai3/bootc-rocm-rhel9, rhelai3/bootc-gaudi-rhel9, rhelai3/bootc-aws-cuda-rhel9, rhelai3/bootc-gcp-cuda-rhel9, rhelai3/bootc-azure-cuda-rhel9, +1 more
    affected: workaround, no fix available “Fix deferred”
  • Red Hat Hardened Images python3.11 3.11.18-1.hum1, python3.13 3.13.18-1.hum1, python3.14 3.14.8-1.el10_2, python3.15 3.15.2-0.1.hum1, python3.10 3.10.22-1.1.hum1, python3.12 3.12.15-1.el10_2
    affected: workaround, no fix available, no fix planned “Will not fix”
  • Red Hat OpenShift Virtualization 4 container-native-virtualization/ocp-virt-validation-checkup-rhel9 Red Hat Self-service automation portal 2 ansible-automation-platform/bootc-automation-portal-rhel9
    affected: workaround, no fix available “Fix deferred”

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
none
Automatable
no
Technical impact
total
Assessed
10d ago

Exploit prediction

0.26% chance of exploitation in the next 30 days, higher than 17% of all scored CVEs (FIRST EPSS, 2026-11-09).

CVSS scores

assigned by version score vector
CNA 4.0 5.3 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
CNA 4.0 5.3 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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

Affected products

  • Python Software Foundation CPython

Classification

Weakness
  • CWE-158 Improper Neutralization of Null Byte or NUL Character

References

Sources

Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

CPEs and fixed versions use Anchore's correction of NVD's data: Added CPE configurations because not yet analyzed by NVD.