🛡️ CVE-2025-48945 on Debian — pycares
Description
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.
Distribution advisory
This page covers CVE-2025-48945 as tracked by Debian, for the package pycares. The fix is available in version 4.9.0-1; earlier versions remain affected.
How this vulnerability can be exploited
This issue can be reached over the network, attack complexity is low, an attacker needs no privileges on the target. No user interaction is required. The scope is unchanged, so the impact stays within the vulnerable component. Rated impact: confidentiality none, integrity none, availability high.
Weakness class
DEBIAN-CVE-2025-48945 is classified as CWE-416: Use After Free. Memory is used after being released, so its contents may already belong to something else.
Affected software
DEBIAN-CVE-2025-48945 is recorded against 1 package.
- pycares (fixed in 4.9.0-1)
Timeline and source
Published on 20 June 2025 and last revised on 4 August 2026. No public exploit is currently recorded for this entry. Record sourced from OSV.
References
CVE-2025-48945 on other distributions
Each distribution ships its own build and its own fixed version. Pick the one you run:
Details
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
| Software | From version | Fixed in |
|---|---|---|
| pycares | — | 4.9.0-1 |
References
Similar Threats
- Unknown UBUNTU-CVE-2025-48945
- Unknown CVE-2025-48945
- Unknown GHSA-c58j-88f5-h53f
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