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 Details
- CVSS 4.0 Base Score: 8.7 (HIGH)
- CVSS 4.0 Vector: (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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X)
- CVSS 3.1 Vector: (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H)
Covered by Rapid7
| Product | Vendor Advisory | Solution File | Added | Published |
|---|---|---|---|---|
| Alma_linux | — | Upgrade python3.12-testUpgrade python3.12-rpm-macrosUpgrade python3.12-idleUpgrade python3.12-debugUpgrade python3.12-tkinterUpgrade python3.12-develUpgrade python3.12Upgrade python3.12-libs | Dec 19, 2024 | Dec 6, 2024 |
| Alpine Linux | — | Upgrade python3 | Aug 8, 2025 | Dec 6, 2024 |
| Amazon_linux_2023 | — | Upgrade python3.12-testUpgrade python3.12-idleUpgrade python3.12-debugsourceUpgrade python3.12Upgrade python3.12-libsUpgrade python3.12-tkinterUpgrade python3.12-debuginfoUpgrade python3.12-debugUpgrade python3.12-devel | Feb 17, 2025 | Dec 6, 2024 |
| Debian | — | Upgrade python3.13 | Jul 27, 2026 | Jul 27, 2026 |
| Oracle_linux | — | Upgrade python3.12-debugUpgrade python3.12-testUpgrade python3.12-idleUpgrade python3.12-libsUpgrade python3.12-tkinterUpgrade python3.12Upgrade python3.12-develUpgrade python3.12-rpm-macros | Dec 12, 2024 | Dec 6, 2024 |
| Redhat_linux | — | Upgrade python3.12-debuginfoUpgrade python3.12-tkinterUpgrade python3.12-idleUpgrade python3.12-debugsourceUpgrade python3.12Upgrade python3.12-develUpgrade python3.12-rpm-macrosUpgrade python3.12-debugUpgrade python3.12-libsUpgrade python3.12-test | Feb 10, 2025 | Dec 6, 2024 |
| Rocky_linux | — | Upgrade python3.12-tkinterUpgrade python3.12-testUpgrade python3.12-debuginfoUpgrade python3.12-develUpgrade python3.12Upgrade python3.12-libsUpgrade python3.12-debugUpgrade python3.12-idleUpgrade python3.12-debugsource | Feb 5, 2026 | Dec 19, 2024 |
| Suse | — | Upgrade python312-toolsUpgrade python313-develUpgrade python313-toolsUpgrade libpython3_13-1_0Upgrade python312-dbmUpgrade python312-develUpgrade python312-testsuiteUpgrade python312-cursesUpgrade python313-baseUpgrade python313-doc-devhelpUpgrade python312-tkUpgrade python312Upgrade libpython3_12-1_0Upgrade python313-tkUpgrade libpython3_13-1_0-x86-64-v3Upgrade python313Upgrade python312-base-32bitUpgrade python312-32bitUpgrade python313-dbmUpgrade python312-baseUpgrade python312-doc-devhelpUpgrade libpython3_12-1_0-32bitUpgrade python312-docUpgrade python313-x86-64-v3Upgrade python313-cursesUpgrade python313-aiohttpUpgrade python312-idleUpgrade python313-base-x86-64-v3Upgrade python313-docUpgrade python313-idle | Jan 9, 2025 | Dec 6, 2024 |
| Ubuntu | — | Upgrade python3.12Upgrade python3.12-minimal | Jan 23, 2025 | Dec 6, 2024 |
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