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🛡️ CVE-2024-12254 — libpython

🟠 CVSS 8.0 — High ✅ No Known Exploit NVD
8.0
CVSS Score
0 Low4 Medium7 High9 Critical10

Description

Unbounded memory buffering in SelectorSocketTransport.writelines()

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.

How this vulnerability can be exploited

This issue can be reached over the network, attack complexity is low, an attacker needs no privileges on the target. No user interaction is required. The scope is unchanged, so the impact stays within the vulnerable component. Rated impact: confidentiality none, integrity none, availability high.

CVSS metrics in full

The score comes from this vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

  • Attack vector: Network — reachable from anywhere that can route to the service.
  • Attack complexity: Low — the attack works reliably, with no preparation.
  • Privileges required: None — an unauthenticated stranger can try it.
  • User interaction: None — nobody has to be tricked into anything.
  • Scope: Unchanged — the damage stays inside the vulnerable component.
  • Confidentiality impact: None.
  • Integrity impact: None.
  • Availability impact: High — total loss, or loss the attacker controls.

Affected software

CVE-2024-12254 is recorded against 4 packages.

  • libpython
  • python
  • python-min
  • unknown

Timeline and source

Published on 11 August 2025. No public exploit is currently recorded for this entry. Record sourced from NVD.

References

www.openwall.com (Web)
github.com (Web)
github.com (Web)
github.com (Web)
github.com (Web)
github.com (Web)
mail.python.org (Web)
nvd.nist.gov (Web)
security.netapp.com (Web)

Other advisories for this package

libpython has other advisories on record. If you are patching this one, these are worth checking on the same host:

CVE-2024-12254 on other distributions

Each distribution ships its own build and its own fixed version. Pick the one you run:

Details

Severity HIGH
CVSS Score 8.0
CVSS Vector CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
CWE N/A
Public Exploit ✅ No
Source NVD
Published 2025-08-11
Updated 2026-08-20
Modified 2025-08-11
Fix URL N/A

Affected Packages

Software From version Fixed in
libpython — —
python — —
python-min — —
unknown — —

Site Security Check

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ⓘ Data Notice: The information presented above has been compiled from publicly available internet sources. Boteraser aggregates this data solely for informational purposes and does not independently classify, evaluate, or endorse any findings about the vulnerabilities listed. The accuracy and completeness of this information is the sole responsibility of the original publishers. Boteraser and its operators accept no liability for any decisions made based on this data.

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