CVE-2021-43896

Executable-code spoofing via ANSI pipeline sequence injection

Published Dec 15, 2021 · Updated Aug 4, 2024

ANSI sequence injection in Microsoft PowerShell 7.2.0 allows local users to alter code as it passes through the pipeline. The pipeline's OutputRendering handling lets specially crafted ANSI control sequences change strings between display and execution. User interaction is required, and the resulting code spoofing can compromise integrity without disclosing data or interrupting service.

CVSS severity5.5
Medium
EPSS probability2.32%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

ANSI sequence injection in Microsoft PowerShell 7.2.0 allows local users to alter code as it passes through the pipeline. The pipeline's OutputRendering handling lets specially crafted ANSI control sequences change strings between display and execution. User interaction is required, and the resulting code spoofing can compromise integrity without disclosing data or interrupting service.

The record

CVE
CVE-2021-43896
Published
Dec 15, 2021
Updated
Aug 4, 2024
Vendor
Microsoft
Product
CBL-Mariner
Classifications
T1204
Attack vector
local
Privileges
unauthenticated

Timeline

How it unfolded

  1. Dec 15, 2021CVE publishedPublication date reported by the CVE source.
  2. Aug 4, 2024Record 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 <7.2.1-1
  2. Affected versionversion=N/A

What conditions does exploitation require?

Attack vectorlocal
Required privilegesunauthenticated

What is affected?

Microsoft · CBL-Marinerversion=1.0 <7.2.1-1; version=N/A
Microsoft · PowerShell 7.2version=7.2.0 <7.2.1

Published CVSS scores

4.3NVDAV:N/AC:M/Au:N/C:N/I:P/A:N
5.5MicrosoftCVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:N
5.5NVDCVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:N

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)
Vectorlocal
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

T1204User Execution

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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