CVE-2026-48095Public exploitNetwork attack vector

Code execution via NTFS stream buffer under-allocation

Published Jun 5, 2026 · Updated Jun 5, 2026

Heap buffer overflow in 7-Zip 26.00 and earlier allows remote attackers to execute code by inducing a user to open a crafted NTFS image. CInStream::GetCuSize() shifts a 32-bit value by 32 for attacker-controlled size fields, allocates _inBuf as one byte, and ReadStream_FALSE writes up to 256 MB into it. Extraction or testing triggers the overflow; 32-bit builds reach it directly, while 64-bit builds require an 8 GB allocation to succeed and otherwise crash.

CVSS severity8.8
High
EPSS probability1.12%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Heap buffer overflow in 7-Zip 26.00 and earlier allows remote attackers to execute code by inducing a user to open a crafted NTFS image. CInStream::GetCuSize() shifts a 32-bit value by 32 for attacker-controlled size fields, allocates _inBuf as one byte, and ReadStream_FALSE writes up to 256 MB into it. Extraction or testing triggers the overflow; 32-bit builds reach it directly, while 64-bit builds require an 8 GB allocation to succeed and otherwise crash.

The record

CVE
CVE-2026-48095
Published
Jun 5, 2026
Updated
Jun 5, 2026
Vendor
7-Zip
Product
7-Zip
Classifications
CWE-787, CWE-190, T1203, T1204.002
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jun 5, 2026CVE publishedPublication date reported by the CVE source.
  2. Jun 5, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=<= 26.00

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

7-Zip · 7-Zipversion=<= 26.00

Published CVSS scores

8.8GitHub, Inc.CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-787Out-of-bounds Write
CWE-190Integer Overflow or Wraparound
T1203Exploitation for Client Execution
T1204.002User Execution Malicious File

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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