CVE-2021-21871: A memory corruption vulnerability exists in the DMG File Format Handler functionality of PowerISO 7.9

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HIGH 7.8DOWNGRADE

CVE-2021-21871 is a high-severity flaw (CVSS 7.8) affecting poweriso. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

A memory corruption vulnerability exists in the DMG File Format Handler functionality of PowerISO 7.9. A specially crafted DMG file can lead to an out-of-bounds write. An attacker can provide a malicious file to trigger this vulnerability. The vendor fixed it in a bug-release of the current version.

Why this priority

High severity
Public exploit reference

No fix is published yet: follow the downgrade or mitigation steps.

Risk facts

CVSS score	7.8 (High)
Attack vector	Local
Attack complexity	Low
Privileges needed	None
User interaction	Required
EPSS exploit chance	0.9% (top 39%)
CISA exploited list	No
Weakness	CWE-787
Published	2021-06-29
Last modified	2026-06-17

Publisher (CNA): Talos · Vendor: poweriso

Last updated 2026-06-17 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2021-06-29 16:15 UTCPublished CVE record published
2026-06-17 03:36 UTCUpdated Record last modified

poweriso poweriso DOWNGRADE

Affected: 7.9

Fixed in: no fixed release known

Safe to downgrade to: a release before 7.9

1. Check installed version

apt-cache policy poweriso || rpm -q poweriso || poweriso --version

2. No fixed release: DOWNGRADE to a release before 7.9 (Debian / Ubuntu)

apt-cache madison poweriso sudo apt install poweriso=<VERSION_BEFORE_7.9> sudo apt-mark hold poweriso

2. No fixed release: DOWNGRADE (RHEL / Amazon Linux / Fedora)

dnf --showduplicates list poweriso sudo dnf downgrade poweriso-<VERSION_BEFORE_7.9> sudo dnf versionlock add poweriso

Downgrade risk

Downgrading can break dependent software and may reopen older bugs. Read the distro advisory first and test on a non-production host.

After downgrade

Restart the service, and keep the package held until a fixed release ships.

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2021-21871?

poweriso: downgrade or apply the listed mitigation. Exact commands for each OS are on this page.

Is CVE-2021-21871 being exploited?

CVE-2021-21871 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2021-21871 affect?

CVE-2021-21871 affects poweriso. Severity is high (CVSS 7.8). A memory corruption vulnerability exists in the DMG File Format Handler functionality of PowerISO 7.9. A specially crafted DMG file can lead to an out-of-bounds write. An attacker can provide a malicious file to trigger this vulnerability.

How urgent is CVE-2021-21871?

Priority 48/100. High severity; Public exploit reference

Related CVEs

CVE-2022-41992 HIGH 7.8 DOWNGRADE A memory corruption vulnerability exists in the VHD File Format parsing CXSPARSE record functionality of Power

References

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