CVE intelligence

CVE-2026-6100

Vulnerability intelligence

Published Apr 13, 2026Sources checked Nov 11, 2026

8.1HIGHCVSS out of 10

What this means

Review the available evidence

CVE-2026-6100 and is rated High severity with a CVSS score of 8.1. It is not in the current CISA KEV record we collected. That does not prove exploitation has not occurred.

What to do next

Remediation and response

Microsoft Security Response Center guidance

Vendor revision: Aug 10, 2026

CBL-Mariner Releases

Vendor-listed releases

3.12.9-14

CISA KEVNot listedBased on the latest collected catalog

EPSS0.6%Estimated 30-day exploitation probability

Ransomware useNot markedCISA KEV ransomware field

Threat actors0Source-linked actor relationships

Overview

What is CVE-2026-6100?

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.

Source: NVD