CVE-2025-48945
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.
Does this matter?
High impact if exploited, but EPSS currently rates exploitation as unlikely (0.45%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.
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.
- CVSS 4.0
- 8.2 HIGHCVSS: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/M
- EPSS
- 0.45% probability · 38th percentile
- CISA KEV
- Not listed
- Weakness
- CWE-416
- Source
- security-advisories@github.com
References
- https://github.com/aio-libs/aiodns/commit/f259a6e3650555157af53ac2b39f2ff545321d55
- https://github.com/aio-libs/aiodns/releases/tag/v3.5.0
- https://github.com/saghul/pycares/commit/ebfd7d71eb8e74bc1057a361ea79a5906db510d4
- https://github.com/saghul/pycares/releases/tag/v4.9.0
- https://github.com/saghul/pycares/security/advisories/GHSA-5qpg-rh4j-qp35
- https://github.com/saghul/pycares/security/advisories/GHSA-5qpg-rh4j-qp35
- https://github.com/saghul/pycares/security/advisories/GHSA-5qpg-rh4j-qp35
- https://github.com/saghul/pycares/security/advisories/GHSA-5qpg-rh4j-qp35
Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.