CVE-2024-12254: DoS (CVSS 7.5)

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.

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CVSS v3.1 Score

7.5

HIGH

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Weakness Type (CWE)

CWE-400 Uncontrolled Resource Consumption

CWE-770 CWE-770

References

Other References

https://github.com/python/cpython/commit/71e8429ac8e2adc10084ab5ec29a62f4b6671a82 https://github.com/python/cpython/commit/9aa0deb2eef2655a1029ba228527b152353135b5 https://github.com/python/cpython/commit/e991ac8f2037d78140e417cc9a9486223eb3e786 https://github.com/python/cpython/issues/127655 https://github.com/python/cpython/pull/127656 https://mail.python.org/archives/list/[email protected]/thread/H4O3UBAOAQQXGT4RE3E4XQYR5XLROORB/ http://www.openwall.com/lists/oss-security/2024/12/06/1 https://security.netapp.com/advisory/ntap-20250404-0010/

Frequently Asked Questions

What is 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. It has a CVSS v3.1 base score of 7.5 (HIGH).

How severe is CVE-2024-12254? +

CVE-2024-12254 has a CVSS v3.1 score of 7.5 out of 10, rated HIGH. This is a high-severity vulnerability that should be prioritized for patching.

How do I check if I'm vulnerable to CVE-2024-12254? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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