CVE-2026-70351Network attack vector

Code execution via undisclosed integer overflow

Published Sep 8, 2026 · Updated Sep 9, 2026

Integer overflow in Microsoft WebP Image Extension before 1.2.31.0 allows remote attackers to execute code through a malicious WebP image. The public record does not identify the decoder routine or integer operation; it states only that wraparound leads to a heap-based buffer overflow. Exploitation requires a user to cause an application to process the image, and successful exploitation runs code in that application's context.

CVSS severity8.8
High
EPSS probability0.82%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Integer overflow in Microsoft WebP Image Extension before 1.2.31.0 allows remote attackers to execute code through a malicious WebP image. The public record does not identify the decoder routine or integer operation; it states only that wraparound leads to a heap-based buffer overflow. Exploitation requires a user to cause an application to process the image, and successful exploitation runs code in that application's context.

The record

CVE
CVE-2026-70351
Published
Sep 8, 2026
Updated
Sep 9, 2026
Vendor
Microsoft
Product
WebP Image Extension
Classifications
CWE-122, CWE-190, T1203, T1204.002
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Sep 8, 2026CVE publishedPublication date reported by the CVE source.
  2. Sep 9, 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=1.0.0.0 <1.2.31.0

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Microsoft · WebP Image Extensionversion=1.0.0.0 <1.2.31.0

Published CVSS scores

8.8MicrosoftCVSS: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.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

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 exploitUnconfirmed

Weakness, pattern, technique

CWE-122Heap-based Buffer Overflow
CWE-190Integer Overflow or Wraparound
T1203Exploitation for Client Execution
T1204.002User Execution: Malicious File

Public exploit references

No public exploit references are available in this record.

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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