CVE-2024-12254

Unbounded memory buffering in SelectorSocketTransport.writelines()

Description

Starting in Python 3.12.0, the asyncio._SelectorSocketTransport.writelines() method would not "pause" writing and signal to the Protocol to drain the buffer to the wire once the write buffer reached the "high-water mark". Because of this, Protocols would not periodically drain the write buffer potentially leading to memory exhaustion. This vulnerability likely impacts a small number of users, you must be using Python 3.12.0 or later, on macOS or Linux, using the asyncio module with protocols, and using .writelines() method which had new zero-copy-on-write behavior in Python 3.12.0 and later. If not all of these factors are true then your usage of Python is unaffected.

Categories

8.7
CVSS
Severity: High
CVSS 4.0 •
CVSS 3.1 •
EPSS 0.14%
Vendor Advisory python.org
Affected: Python Software Foundation CPython
Published at:
Updated at:

References

Frequently Asked Questions

What is the severity of CVE-2024-12254?
CVE-2024-12254 has been scored as a high severity vulnerability.
How to fix CVE-2024-12254?
To fix CVE-2024-12254, make sure you are using an up-to-date version of the affected component(s) by checking the vendor release notes. As for now, there are no other specific guidelines available.
Is CVE-2024-12254 being actively exploited in the wild?
As for now, there are no information to confirm that CVE-2024-12254 is being actively exploited. According to its EPSS score, there is a ~0% probability that this vulnerability will be exploited by malicious actors in the next 30 days.
What software or system is affected by CVE-2024-12254?
CVE-2024-12254 affects Python Software Foundation CPython.
This platform uses data from the NIST NVD, MITRE CVE, MITRE CWE, First.org and CISA KEV but is not endorsed or certified by these entities. CVE is a registred trademark of the MITRE Corporation and the authoritative source of CVE content is MITRE's CVE web site. CWE is a registred trademark of the MITRE Corporation and the authoritative source of CWE content is MITRE's CWE web site.
© 2025 Under My Watch. All Rights Reserved.