Attack ChainAIDerived
Hypothetical attack flow derived from CVE metadata – not a confirmed exploit chain
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AccessHost crafted content on network resource
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ExploitSocially engineer victim to run it in PowerShell
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ExecutionFlawed security check fails to block operation
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ImpactBypass security feature, tamper with protected integrity
Vulnerability Assessment
| Weakness |
CWE
ASVS 5.0
V12 - Secure Communication Improperly implemented security check
|
| Exploitation Conditions | Exploitation requires a user in a vulnerable PowerShell 7.x build (7.4.0-7.4.20, 7.5.0-7.5.11, or 7.6.0-7.6.6) to interact with attacker-supplied content - the CVSS UI:R metric confirms a required victim action, so this cannot be triggered silently or server-side without a human running the malicious input. No authentication or prior privileges are needed (PR:N). The practical limiting factor is this mandatory user interaction combined with the single impact being an integrity-only security-check bypass (C:N/A:N); the description does not name the exact feature bypassed, so defenders cannot scope it to a specific configuration or execution mode from the available data. Systems patched to 7.4.21 / 7.5.12 / 7.6.7 or later are not affected. |
| Impact | This is a moderate, not high-urgency, issue. The CVSS 3.1 vector (AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:N, base 6.5) describes a network-reachable, unauthenticated, low-complexity security-feature bypass whose only impact is to integrity (I:H) - there is no confidentiality or availability loss and no scope change. Crucially, exploitation requires user interaction (UI:R), which breaks any fully-automated, wormable exploitation path. Every corroborating signal points to low real-world urgency: CISA's SSVC decision framework reports Exploitation=none, Automatable=no, and Technical Impact=partial, which is consistent with the UI:R dependency and the single-impact profile. There is no CISA KEV listing and no EPSS score was provided, so there is no public evidence of active exploitation or any quantified exploitation probability - treat exploitation likelihood as unquantified rather than low. No conflicting signals were observed between the vector and the description (both describe a network security-feature bypass). Bottom line: a legitimately network-exploitable but user-interaction-gated feature bypass in a developer/admin tool - worth patching on a normal cycle, but not an emergency given no exploitation evidence and the required victim action. |
| Exploit ScenarioDerived | An attacker crafts malicious content (e.g., a script, module, or serialized object) and lures a victim into opening or executing it in a vulnerable PowerShell 7.x session, where the improperly implemented security check fails to block the disallowed operation. Because user interaction is required (UI:R), the attack depends on social engineering rather than silent remote triggering. No public exploit code has been identified at time of analysis. |
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Alert meAnalysisAIv1 – Oct 14, 2026
Security feature bypass in Microsoft PowerShell 7.x allows an attacker to defeat a built-in protective control in the affected runtime, with the integrity impact scored as high while confidentiality and availability are unaffected. The flaw affects PowerShell 7.4 before 7.4.21, 7.5 before 7.5.12, and 7.6 before 7.6.7, and exploitation requires a victim to interact with attacker-supplied content (CVSS UI:R), so it cannot be triggered silently or server-side without a human running the malicious input; no authentication or prior privileges are needed. No public exploit code or active exploitation has been identified at time of analysis (CISA SSVC records Exploitation: none), and a vendor patch is available, making this a moderate rather than high-urgency issue. Note that the vendor description does not name the specific security feature being bypassed, which limits defenders' ability to scope the issue to a particular configuration or execution mode.
RemediationAI
Apply the vendor-released patch by upgrading PowerShell to 7.4.21, 7.5.12, or 7.6.7 (or a later build in the same servicing line); fixes are documented in the Microsoft advisory at https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-96303, and because all three maintenance lines are affected, environments pinned to an older major line must move to the corresponding patched minor. Because exploitation requires a victim to open or run attacker-supplied content (UI:R), the most effective interim control is to block execution of untrusted PowerShell scripts and modules from email, downloads, and removable media, paired with application allowlisting or WDAC/AppLocker policies that only permit signed, approved scripts - the trade-off is added administrative overhead and potential breakage of legitimate automation. Constrained Language Mode or a hardened, non-interactive execution profile can reduce exposure for high-risk users, but note that the vendor description does not disclose which specific control is bypassed, so such restrictions cannot be guaranteed to close the gap on their own and should be treated as defense in depth rather than a substitute for patching. Users should also be trained to treat unsolicited PowerShell scripts or modules as hostile, since the required user action is the primary attack precondition; no public exploit code or active exploitation has been confirmed, so emergency change windows are not warranted - standard patch-cycle prioritization is sufficient.
Affected VersionsENISA
Affected Packages
Source: OSV (Open Source Vulnerabilities)
Affects your stack
Affects 3 packages in euvd
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Technical ContextAI · show details
CVE-2026-96303 is rooted in CWE-358, "Improperly Implemented Security Check for Standard," which describes a control that was intended to enforce a specification or behavioral rule but was implemented incompletely or incorrectly, so the check can be sidestepped rather than cryptographically defeated. In PowerShell this class of defect typically means a guardrail such as an execution/trust policy, script-block inspection hook, or language-mode restriction does not cover every code path that reaches the same capability, allowing crafted content to pass through the check while still performing the restricted action. PowerShell is the cross-platform, .NET-based automation shell and scripting engine that ships as PowerShell 7.x alongside Windows PowerShell 5.1; the affected builds span three parallel servicing lines (7.4, 7.5, and 7.6), all of which are still receiving updates. The CVSS vector CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:N describes a network-reachable, low-complexity, unauthenticated attack that hinges entirely on a required victim action, with the sole scored impact being to integrity of the protected control; confidentiality and availability are explicitly not affected. Neither the input data nor the vendor advisory identifies the precise feature bypassed, and no CPE strings were supplied in the available intelligence, so the affected scope should be treated as the full PowerShell 7.x servicing lines listed rather than a narrower component. The ENISA EUVD entry (EUVD-2026-100222) mirrors the vendor ranges, and CISA's SSVC decision framework rates this as not automatable with only partial technical impact.
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Severity by source
AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:N
Network-reachable security-feature bypass needing no privileges but a victim action (UI:R); integrity-only impact (I:H, C/A:N) with no scope change, matching a feature-bypass with no data disclosure.
Primary rating from Vendor (microsoft).
CVSS VectorVendor: microsoft
Lifecycle Timeline
2DescriptionCVE.org
Improperly implemented security check for standard in Microsoft PowerShell allows an unauthorized attacker to bypass a security feature over a network.
Threat Intelligence Overview
How this decision was reached
The engine reads each signal below and applies a fixed list of rules from top to bottom. The first rule that matches sets the recommended action – like a statement, every line is shown.
What every action level means
SSVC AssessmentENISA
Priority Score
Attack Technique
Authentication bypass attacks exploit flaws in the verification mechanisms that control access to systems and applications.
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EUVD-2026-100222
GHSA-p862-mv9f-9294
NVD
CVE.org
EPSS
Vulnrichment
Exploit-DB