CVE-2021-21871Public exploitNetwork attack vector

Memory corruption via unchecked DMG decompression output

Published Jun 29, 2021 · Updated Aug 3, 2024

Out-of-bounds writes in PowerISO 7.9 allow context-dependent attackers to corrupt process memory through a crafted DMG file. PowerISO's DMG handler inflates malformed ZLIB DIST or DISTEX codes without correctly enforcing the destination buffer limit. Opening the file is required; the demonstrated consequence is an access-violation crash from an invalid pointer write.

CVSS severity8.8
High
EPSS probability0.95%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Out-of-bounds writes in PowerISO 7.9 allow context-dependent attackers to corrupt process memory through a crafted DMG file. PowerISO's DMG handler inflates malformed ZLIB DIST or DISTEX codes without correctly enforcing the destination buffer limit. Opening the file is required; the demonstrated consequence is an access-violation crash from an invalid pointer write.

The record

CVE
CVE-2021-21871
Published
Jun 29, 2021
Updated
Aug 3, 2024
Vendor
PowerISO Computing, Inc.
Product
PowerISO
Classifications
CWE-787, T1203, T1204.002
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jun 29, 2021CVE publishedPublication date reported by the CVE source.
  2. Aug 3, 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=PowerISO 7.9

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

PowerISO Computing, Inc. · PowerISOversion=PowerISO 7.9

Published CVSS scores

8.8Cisco TalosCVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
7.8NIST NVDCVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
6.8NIST NVDAV:N/AC:M/Au:N/C:P/I:P/A:P

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
T1203Exploitation for Client Execution
T1204.002Malicious 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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