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CVE-2026-48095

· Published 05/06/2026 15:16 · Modified 05/06/2026 16:01

Labels: CVE-2026-48095 2026-06-05CVE-2026-48095CWE-190[email protected]

Essential information

Published
05/06/2026 15:16
Modified
05/06/2026 16:01
Author
Creator
CVSS
8.8 HIGH (v3.1)
CISA KEV
No
CWE
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

CVSS metrics

Description

7-Zip is a file archiver with a high compression ratio. Versions 26.00 and prior contain a heap buffer overflow vulnerability caused by an under-allocation in the NTFS compressed stream buffer (GetCuSize shift UB), potentially allowing attackers to cause arbitrary code execution or application crashes. CInStream::GetCuSize() in the NTFS handler computes the compression-unit buffer size as (UInt32)1 << (BlockSizeLog + CompressionUnit), and a crafted image with ClusterSizeLog >= 28 and CompressionUnit == 4 drives the exponent to 32, which is undefined behavior and collapses on x86/x64 so _inBuf is allocated as 1 byte. ReadStream_FALSE then writes up to 256 MB of attacker-controlled data into that 1-byte buffer in 64 KB iterations, and because the CInStream object sits only 304 bytes after _inBuf, its vtable pointer is overwritten and the next dispatched call achieves a vtable hijack. On 32-bit builds the overflow is unconditionally reached; on 64-bit it requires the parallel 8 GB _outBuf allocation to succeed, otherwise failing closed to denial of service. The NTFS handler is enabled by default in stock 7z.dll and, via signature-based fallback matching "NTFS " at offset 3, will open a crafted image regardless of file extension during extraction or testing. Version 26.01 fixes the issue.

NVD status

Status
Undergoing Analysis — CVE has been recently published to the CVE List and has been received by the NVD.
Source
[email protected]
NVD
View on NVD

Affected products (CPE)

ProductCPE
7-zip / 7-zip cpe:2.3:a:7-zip:7-zip:<26.00:*:*:*:*:*:*:*
7-zip / 7-zip cpe:2.3:a:7-zip:7-zip:26.01:*:*:*:*:*:*:*

References