Threat Intelligence / CVE / CVE-2026-48095

CVE-2026-48095 — mcmilk 7-Zip

CVSS v3.1 8.8 (HIGH) · EPSS 0.0% (higher than 19.2% of all scored CVEs) · Priority 5.2/10 · Published 2026-06-05

As of 2026-06-08, CVE-2026-48095 is a HIGH-severity vulnerability in mcmilk 7-Zip, CVSS v3.1 8.8, EPSS 0.0% (19.2th percentile). Threadlinqs Intelligence links 1 tracked threat campaign to CVE-2026-48095, most recently “7-Zip NTFS Handler Heap Overflow CVE-2026-48095 — vtable Hijack via Crafted Archive (GHSL-2026-140)”.

Last updated: 2026-06-08

What is CVE-2026-48095?

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 = 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.

The record classifies CVE-2026-48095 under weakness classes CWE-787, CWE-190. Its CVSS v3 base vector states that the flaw is reachable remotely over the network, needs no prior authentication, needs a user to take an action first, and has high impact on confidentiality, integrity, availability. 1 affected-product entry is recorded, across 1 vendor, listed below. The identifier was first published 108 days ago.

Severity and exploitation probability

CVSS v3.1 base score: 8.8 — HIGH
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
EPSS (FIRST): 0.0% probability of exploitation in the next 30 days, higher than 19.2% of all scored CVEs
CISA KEV: Not listed in the CISA Known Exploited Vulnerabilities catalog
Threadlinqs priority: 5.2/10 — a Threadlinqs composite of the CVSS base score, the EPSS percentile and public exploit availability
Published: 2026-06-05, last modified 2026-06-08

Is CVE-2026-48095 being exploited?

It currently carries a trending score of 13 in the Threadlinqs vulnerability feed.

Affected products and versions

mcmilk: 7-Zip

How to fix CVE-2026-48095

No vendor patch reference has been recorded for CVE-2026-48095 in the tracked sources. Follow the references below for a fix, and treat the products listed above as exposed until the vendor states otherwise.

Threat activity tracking CVE-2026-48095

1 tracked threat in the Threadlinqs corpus references CVE-2026-48095, either in the campaign’s CVE list or as an indicator on the campaign record.

7-Zip NTFS Handler Heap Overflow CVE-2026-48095 — vtable Hijack via Crafted Archive (GHSL-2026-140) — HIGH · 2026-05-26

Sources

Seeded from cveorg and not yet processed by the Threadlinqs enrichment pipeline, so blank CVSS, EPSS or KEV fields above mean NOT MEASURED rather than measured-absent.

Full detection coverage & IOCs for threats exploiting CVE-2026-48095 are available via the Threadlinqs MCP server (Purple tier). View plans →

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