Описание
Use-after-free (UAF) was possible in the lzma.LZMADecompressor, bz2.BZ2Decompressor, and gzip.GzipFile when a memory allocation fails with a MemoryError and the decompression instance is re-used. This scenario can be triggered if the process is under memory pressure. The fix cleans up the dangling pointer in this specific error condition.
The vulnerability is only present if the program re-uses decompressor instances across multiple decompression calls even after a MemoryError is raised during decompression. Using the helper functions to one-shot decompress data such as lzma.decompress(), bz2.decompress(), gzip.decompress(), and zlib.decompress() are not affected as a new decompressor instance is used per call. If the decompressor instance is not re-used after an error condition, this usage is similarly not vulnerable.
A flaw was found in Python's decompression modules, including lzma.LZMADecompressor, bz2.BZ2Decompressor, and gzip.GzipFile. This vulnerability, a use-after-free, can occur if a program attempts to re-use a decompression object after a memory allocation error, especially when the system is experiencing high memory usage. Exploitation of this flaw could potentially allow an attacker to execute arbitrary code or access sensitive data. The vulnerability is only present if the program re-uses decompressor instances across multiple decompression calls even after a MemoryError is raised during decompression. Using the helper functions to one-shot decompress data such as lzma.decompress(), bz2.decompress(), gzip.decompress(), and zlib.decompress() are not affected as a new decompressor instance is used per call. If the decompressor instance is not re-used after an error condition, this usage is similarly not vulnerable.
Отчет
The severity of this flaw is somewhat mitigated on Red Hat platforms. By default processes are not executed with root user privilege and are limited in their scope which in turn limits the impact of this flaw.
Меры по смягчению последствий
Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability.
Затронутые пакеты
| Платформа | Пакет | Состояние | Рекомендация | Релиз |
|---|---|---|---|---|
| Red Hat Enterprise Linux 6 | python | Out of support scope | ||
| Red Hat Enterprise Linux 7 | python | Out of support scope | ||
| Red Hat Enterprise Linux 7 | python3 | Affected | ||
| Red Hat Enterprise Linux 8 | python36:3.6/python36 | Not affected | ||
| Red Hat Enterprise Linux 8 | python39-devel:3.9/python39 | Not affected | ||
| Red Hat Enterprise Linux AI (RHEL AI) 3 | redhat-user-workloads/bootc-cuda-aws-3-3 | Affected | ||
| Red Hat Enterprise Linux AI (RHEL AI) 3 | redhat-user-workloads/bootc-cuda-azure-3-3 | Affected | ||
| Red Hat Enterprise Linux AI (RHEL AI) 3 | redhat-user-workloads/bootc-cuda-gcp-3-3 | Affected | ||
| Red Hat Enterprise Linux AI (RHEL AI) 3 | redhat-user-workloads/bootc-rocm-azure-3-3 | Affected | ||
| Red Hat Enterprise Linux 10 | python3.12 | Fixed | RHSA-2026:10711 | 27.04.2026 |
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Дополнительная информация
Статус:
EPSS
8.1 High
CVSS3
Связанные уязвимости
Use-after-free (UAF) was possible in the `lzma.LZMADecompressor`, `bz2.BZ2Decompressor`, and `gzip.GzipFile` when a memory allocation fails with a `MemoryError` and the decompression instance is re-used. This scenario can be triggered if the process is under memory pressure. The fix cleans up the dangling pointer in this specific error condition. The vulnerability is only present if the program re-uses decompressor instances across multiple decompression calls even after a `MemoryError` is raised during decompression. Using the helper functions to one-shot decompress data such as `lzma.decompress()`, `bz2.decompress()`, `gzip.decompress()`, and `zlib.decompress()` are not affected as a new decompressor instance is used per call. If the decompressor instance is not re-used after an error condition, this usage is similarly not vulnerable.
Use-after-free (UAF) was possible in the `lzma.LZMADecompressor`, `bz2.BZ2Decompressor`, and `gzip.GzipFile` when a memory allocation fails with a `MemoryError` and the decompression instance is re-used. This scenario can be triggered if the process is under memory pressure. The fix cleans up the dangling pointer in this specific error condition. The vulnerability is only present if the program re-uses decompressor instances across multiple decompression calls even after a `MemoryError` is raised during decompression. Using the helper functions to one-shot decompress data such as `lzma.decompress()`, `bz2.decompress()`, `gzip.decompress()`, and `zlib.decompress()` are not affected as a new decompressor instance is used per call. If the decompressor instance is not re-used after an error condition, this usage is similarly not vulnerable.
Use-after-free in lzma.LZMADecompressor, bz2.BZ2Decompressor, and gzip.GzipFile after re-use under memory pressure
Use-after-free (UAF) was possible in the `lzma.LZMADecompressor`, `bz2 ...
Use-after-free (UAF) was possible in the `lzma.LZMADecompressor`, `bz2.BZ2Decompressor`, and `gzip.GzipFile` when a memory allocation fails with a `MemoryError` and the decompression instance is re-used. This scenario can be triggered if the process is under memory pressure. The fix cleans up the dangling pointer in this specific error condition. The vulnerability is only present if the program re-uses decompressor instances across multiple decompression calls even after a `MemoryError` is raised during decompression. Using the helper functions to one-shot decompress data such as `lzma.decompress()`, `bz2.decompress()`, `gzip.decompress()`, and `zlib.decompress()` are not affected as a new decompressor instance is used per call. If the decompressor instance is not re-used after an error condition, this usage is similarly not vulnerable.
EPSS
8.1 High
CVSS3