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Fencer Vulns
high 8.2

CVE-2025-48945 json

pycares has a Use-After-Free Vulnerability

published 2025-06-16 16 mo ago modified 2026-09-10 1 mo ago also GHSA-5qpg-rh4j-qp35 , EUVD-2025-28273

cvss
8.2
version 4.0, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.5%
EPSS 0.5% chance of exploitation in 30 days, percentile 42%
public exploits
0
none known

Summary

pycares is a Python module which provides an interface to c-ares. c-ares is a C library that performs DNS requests and name resolutions asynchronously. Prior to version 4.9.0, pycares is vulnerable to a use-after-free condition that occurs when a Channel object is garbage collected while DNS queries are still pending. This results in a fatal Python error and interpreter crash. The vulnerability has been fixed in pycares 4.9.0 by implementing a safe channel destruction mechanism.

Patch / fix

  • pypi pycares 4.9.0
  • pycares Debian 14 4.9.0-1

debian advisories DEBIAN-CVE-2025-48945

  • python-pycares SLES for SAP 15 SP5, SLES for SAP 15 SP4, SLES 15 SP5-LTSS +8 more 4.10.0-150400.9.8.1

suse advisories SUSE-SU-2025:03354-1

  • python-pycares openSUSE Tumbleweed 4.9.0-1.1

opensuse advisories openSUSE-SU-2025:15324-1

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-2025-48945 updated cvss 5.5

pycares: pycares Channel Use-After-Free

  • Red Hat Ansible Automation Platform 2 python-pycares, python3x-pycares, python3.11-pycares, automation-controller Red Hat Satellite 6 python-pycares, python3-pycares Red Hat Update Infrastructure 4 for Cloud Providers python-pycares
    not affected: vulnerable code not present

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
partial
Assessed
16 mo ago

Exploit prediction

0.48% chance of exploitation in the next 30 days, higher than 42% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 4.0 8.2 CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N
CNA 4.0 8.2 CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/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 packages

ecosystem package affected fixed in
pypi pycares
<4.9.0
4.9.0

Affected products

  • aio-libs aiodns

Classification

Weakness

References

Sources

Fencer Vulns 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.