CVE-2026-70338

Security feature bypass via inconsistent dot-sourcing checks

Published Aug 11, 2026 · Updated Aug 25, 2026

Code injection in Microsoft PowerShell before 7.4.19.0, 7.5.10.0, and 7.6.5 allows local users to bypass a security feature via pwsh -File. The advanced-script CommandProcessor path invokes ValidateCompatibleLanguageMode for dotted scripts without the rethrow-exit guard that the simple-script path already uses, so signed advanced-function scripts are handled differently under WDAC and Constrained Language Mode. Reachability is local and depends on executing a signed advanced-function script in a locked-down environment; the bypass weakens language-mode enforcement for that run rather than exposing a remote path.

CVSS severity7.8
High
EPSS probability0.31%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Code injection in Microsoft PowerShell before 7.4.19.0, 7.5.10.0, and 7.6.5 allows local users to bypass a security feature via pwsh -File. The advanced-script CommandProcessor path invokes ValidateCompatibleLanguageMode for dotted scripts without the rethrow-exit guard that the simple-script path already uses, so signed advanced-function scripts are handled differently under WDAC and Constrained Language Mode. Reachability is local and depends on executing a signed advanced-function script in a locked-down environment; the bypass weakens language-mode enforcement for that run rather than exposing a remote path.

The record

CVE
CVE-2026-70338
Published
Aug 11, 2026
Updated
Aug 25, 2026
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-94, T1059.001
Attack vector
local
Privileges
unauthenticated

Timeline

How it unfolded

  1. Aug 11, 2026CVE publishedPublication date reported by the CVE source.
  2. Aug 25, 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?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectorlocal
Required privilegesunauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

7.8NVDCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
7.8Microsoft CorporationCVSS:3.1/AV:L/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)
Vectorlocal
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-94Improper Control of Generation of Code ('Code Injection')
T1059.001PowerShell

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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