---
cve: "CVE-2024-12254"
severity: "HIGH"
cvss: 8.7
epss: "1.9%"
vendor: "Python Software Foundation"
kev: false
exploited: false
published: "2024-12-06 16:15:20"
tags: [cve, security, high]
source: tsecurity.de CVE-Dossier
exported: "2026-09-06T06:34:15+02:00"
---

# CVE-2024-12254

> 8.7 HIGH · 🧪 PoC

## Beschreibung

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.

## CVSS-Vektor

```
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N
```

| Metrik | Wert | Bewertung |
|---|---|---|
| AV Angriffsvektor | Netzwerk | bad |
| AC Komplexität | Gering | bad |
| PR Privilegien | Keine | bad |
| UI Interaktion | Keine | bad |

## Patch verfügbar (OSV)

- fdb81425a9ad683f8c24bf5cbedc9b96baf00cd2 (Commit)
- 4f8bb3947cfbc20f970ff9d9531e1132a9e95396 (Commit)

## Referenzen

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

---
_Exportiert aus dem [tsecurity.de CVE-Dossier](https://tsecurity.de/cve?cve=CVE-2024-12254) · Datenquellen: EUVD (ENISA), NVD, OSV, CISA KEV, FIRST EPSS, Exploit-DB, BSI BITS_