CVE-2021-40589Network attack vector

Unspecified impact via underflowed BMP palette allocation

Published Jun 8, 2022 · Updated Aug 4, 2024

Integer underflow in ZAngband zangband-data 2.7.5 allows remote attackers to trigger unspecified impact through a crafted BMP file. The BMP loader in src/tk/plat.c subtracts 54 from the untrusted bfOffBits header field without a lower-bound check, so ncol wraps and drives a large palette allocation. The public report does not identify the file-delivery interface or establish whether the allocation causes a crash, memory exhaustion, or another concrete consequence.

CVSS severity9.8
Critical
EPSS probability1.23%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Integer underflow in ZAngband zangband-data 2.7.5 allows remote attackers to trigger unspecified impact through a crafted BMP file. The BMP loader in src/tk/plat.c subtracts 54 from the untrusted bfOffBits header field without a lower-bound check, so ncol wraps and drives a large palette allocation. The public report does not identify the file-delivery interface or establish whether the allocation causes a crash, memory exhaustion, or another concrete consequence.

The record

CVE
CVE-2021-40589
Published
Jun 8, 2022
Updated
Aug 4, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-191
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jun 8, 2022CVE 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?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

7.5NIST NVDAV:N/AC:L/Au:N/C:P/I:P/A:P
9.8NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

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.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

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 exploitUnconfirmed

Weakness, pattern, technique

CWE-191Integer Underflow (Wrap or Wraparound)

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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