CVE-2026-6100
highpriority · track · 0EPSS 0.008 · 55 %ileCHDEEURUUSEPSS · scored 2026-10-22
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.
remediations
Vendor fix, mitigation, or workaround guidance, as published by each source.
No fix is available; mitigate or reduce exposure.
- No fix availableLabX Standardmettler_toledo_psirt
This vulnerability will be fixed in the upcoming releases
cvss
Technical severity, 0–10. One row per scoring source.
base score 0–10 · higher = more severe · hover a vector to decode⚠ sources disagree · medium–critical · 6.9–9.1
ssvc
A stakeholder decision — act, attend, or track — from exploitation and impact.
weaknesses
The CWE weakness classes this flaw belongs to.
affected products (43)
Products and version ranges known to be affected.
- Red Hat Enterprise Linux Update Infrastructure 5.1all versionscert_bundDEcpe:/o:redhat:enterprise_linux:update_infrastructure_5.1
advisories (9)
Vendor and ecosystem advisories describing this.
- VDE-2026-088METTLER TOLEDO: LabX Standard and Enterprise Report on External Component Analysis - v21.42026-08-20csaf · mettler_toledo_psirtCH
The vulnerabilities found in LabX Standard versions 21.3.22 - 21.4.23 are CVE-2025-69419, CVE-2026-0915, CVE-2025-15467, CVE-2026-4800, CVE-2026-33186, CVE-2026-39821, CVE-2026-33671 and are fixed in LabX Standard v21.4.25. The vulnerabilities found in LabX Enterprise versions 21.3.22 - 21.4.23 are CVE-2026-4800, CVE-2026-33186, CVE-2026-39821, CVE-2026-33671 and are fixed in LabX Enterprise v21.4.25 All other vulnerabilities are to be fixed in the upcoming releases.
- WID-SEC-W-2026-1087CPython: Mehrere SchwachstellenDeutsch2026-04-13csaf · cert_bundDE
Ein Angreifer kann mehrere Schwachstellen in Python ausnutzen, um Sicherheitsvorkehrungen zu umgehen, und um Daten zu manipulieren.
- WID-SEC-W-2026-1666IBM QRadar SIEM: Mehrere SchwachstellenDeutsch2026-05-25csaf · cert_bundDE
Ein Angreifer kann mehrere Schwachstellen in IBM QRadar SIEM ausnutzen, um beliebigen Programmcode auszuführen, um seine Privilegien zu erhöhen, um einen Denial of Service Angriff durchzuführen, um Informationen offenzulegen, und um Sicherheitsvorkehrungen zu umgehen.
- WID-SEC-W-2026-2455Oracle Solaris Drittanbieterkomponenten: Mehrere SchwachstellenDeutsch2026-07-21csaf · cert_bundDE
Ein entfernter, anonymer oder authentisierter Angreifer kann mehrere Schwachstellen in verschiedenen Komponenten von Drittanbietern in Oracle Solaris ausnutzen, um einen nicht näher spezifizierten Angriff durchzuführen.
- BIT-libpython-2026-6100Use-after-free in lzma.LZMADecompressor, bz2.BZ2Decompressor, and gzip.GzipFile after re-use under memory pressure2026-07-06vendor · osvUS
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.
- BIT-python-2026-6100Use-after-free in lzma.LZMADecompressor, bz2.BZ2Decompressor, and gzip.GzipFile after re-use under memory pressure2026-07-06vendor · osvUS
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.
- BIT-python-min-2026-6100Use-after-free in lzma.LZMADecompressor, bz2.BZ2Decompressor, and gzip.GzipFile after re-use under memory pressure2026-07-06vendor · osvUS
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.
- PSF-0000-CVE-2026-61002026-04-13vendor · osvUS
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.
- PSF-2026-182026-04-13vendor · osvUS
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.
also known as (8)
Other names and identifiers for this entity.
- CNNVD-202604-2545cnnvd
- EUVD-2026-22028enisa_euvd
- BDU:2026-05838fstec_bdu
- BIT-libpython-2026-6100osv
- BIT-python-2026-6100osv
- BIT-python-min-2026-6100osv
- PSF-0000-CVE-2026-6100osv
- PSF-2026-18osv
sources
Which sources assert this record, and when.
references (72)
External citations — patches, advisories, analysis.
- http://www.openwall.com/lists/oss-security/2026/04/13/10cnnvd
- https://github.com/python/cpython/commit/6a5f79c8d7bbf22b083b240910c7a8781a59437dcnnvd
- https://github.com/python/cpython/commit/8fc66aef6d7b3ae58f43f5c66f9366cc8cbbfcd2cnnvd
- https://github.com/python/cpython/commit/c3cf71c3366fe49acb776a639405c0eea6169c20cnnvd
- https://github.com/python/cpython/issues/148395cnnvd
- https://github.com/python/cpython/pull/148396cnnvd
- https://mail.python.org/archives/list/security-announce@python.org/thread/HTWB2Z6KT5QQX4RYEZAFININDHNOSIF3/cnnvd
- https://www.python.org/Patchcnnvd
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