Resource exhaustion in Python Software Foundation Cpython
CVE-2024-12254
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.
Vulnerability class: DoS (Denial of Service)
EPSS: 0.019 (77.3th percentile) — read the EPSS interpretation.
CVSS v3 metric
CVSS v3 base score 7.5 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H.
Affected products
- Python Software Foundation Cpython — versions 0, 3.14.0a1, 3.13.0
Weakness classification (CWE)
Public proof-of-concept exploits
References
- cna@python.org (issue-tracking)
- cna@python.org (patch)
- cna@python.org (vendor-advisory)
- cna@python.org (patch)
- cna@python.org (patch)
- cna@python.org (patch)
- af854a3a-2127-422b-91ae-364da2661108
- af854a3a-2127-422b-91ae-364da2661108
Frequently asked questions
- What is CVE-2024-12254?
- CVE-2024-12254 is a high-severity vulnerability in Python Software Foundation Cpython, classified under Uncontrolled Resource Consumption. CVSS score: 7.5/10. Published 2024-12-06.
- How severe is CVE-2024-12254?
- High severity. CVSS v3 base score is 7.5 out of 10.
- Is CVE-2024-12254 known to be exploited?
- 3 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.