CVEvulnerability

CVE-2026-6100

9.1 CRITICAL Published 2026-04-13 Modified 2026-10-26 Official page ↗
Status
Awaiting Analysis
Published
2026-04-13
Last modified
2026-10-26
Assigner
[email protected]
CVSS 4.0 ([email protected])
9.1 CRITICAL — CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:H/VI:H/VA:N/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 (0b0ca135-0b70-47e7-9f44-1890c2a1c46c)
8.1 HIGH — CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
Weaknesses
CWE-416, CWE-787, CWE-825

Description

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.

Related

Weakness · CWE (3)

  • CWE-416 Use After Free weakness
  • CWE-787 Out-of-bounds Write weakness
  • CWE-825 Expired Pointer Dereference weakness

References