CVE-2021-40589: ZAngband zangband-data 2.7.5 is affected by an integer underflow vulnerability in src/tk/plat.c through the va

This week

CRITICAL 9.8REMOTEDOWNGRADE

CVE-2021-40589 is a critical-severity flaw (CVSS 9.8) affecting zangband-data. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

ZAngband zangband-data 2.7.5 is affected by an integer underflow vulnerability in src/tk/plat.c through the variable fileheader.bfOffBits.

Why this priority

Critical severity
Public exploit reference
Remotely exploitable, no login, no user action

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

Risk facts

CVSS score	9.8 (Critical)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	1.4% (top 28%)
CISA exploited list	No
Weakness	CWE-191
Published	2022-06-08
Last modified	2026-06-17

Publisher (CNA): MITRE · Vendor: zangband-data project

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

Am I affected?

Timeline

2022-06-08 18:15 UTCPublished CVE record published
2026-06-17 04:07 UTCUpdated Record last modified

zangband-data project zangband-data DOWNGRADE

Affected: 2.7.5

Fixed in: no fixed release known

Safe to downgrade to: a release before 2.7.5

1. Check installed version

apt-cache policy zangband-data || rpm -q zangband-data || zangband-data --version

2. No fixed release: DOWNGRADE to a release before 2.7.5 (Debian / Ubuntu)

apt-cache madison zangband-data sudo apt install zangband-data=<VERSION_BEFORE_2.7.5> sudo apt-mark hold zangband-data

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

dnf --showduplicates list zangband-data sudo dnf downgrade zangband-data-<VERSION_BEFORE_2.7.5> sudo dnf versionlock add zangband-data

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-2021-40589?

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

Is CVE-2021-40589 being exploited?

CVE-2021-40589 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-2021-40589 affect?

CVE-2021-40589 affects zangband-data. Severity is critical (CVSS 9.8). ZAngband zangband-data 2.7.5 is affected by an integer underflow vulnerability in src/tk/plat.c through the variable fileheader.bfOffBits.

How urgent is CVE-2021-40589?

Priority 62/100. Critical severity; Public exploit reference; Remotely exploitable, no login, no user action

References

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