CVE-2021-3548Public exploit

Memory disclosure and crash via unchecked memcpy length

Published May 26, 2021 · Updated Aug 3, 2024

Out-of-bounds read in dmg2img through 20170502 allows local users to disclose process memory or crash the converter via a crafted DMG file. The main function passes the attacker-controlled parts[i].BlocksRunCount multiplied by 0x28 to memcpy without checking it against the decoded buffer length. Exploitation requires a user to process the crafted image; a heap over-read and abort are demonstrated, while the source reports code execution only as a chained possibility.

CVSS severity7.1
High
EPSS probability0.91%
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 read in dmg2img through 20170502 allows local users to disclose process memory or crash the converter via a crafted DMG file. The main function passes the attacker-controlled parts[i].BlocksRunCount multiplied by 0x28 to memcpy without checking it against the decoded buffer length. Exploitation requires a user to process the crafted image; a heap over-read and abort are demonstrated, while the source reports code execution only as a chained possibility.

The record

CVE
CVE-2021-3548
Published
May 26, 2021
Updated
Aug 3, 2024
Vendor
dmg2img Project
Product
dmg2img
Classifications
CWE-125, T1204.002
Attack vector
local
Privileges
unauthenticated

Timeline

How it unfolded

  1. May 26, 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=dmg2img through 20170502

What conditions does exploitation require?

Attack vectorlocal
Required privilegesunauthenticated

What is affected?

dmg2img Project · dmg2imgversion=dmg2img through 20170502

Published CVSS scores

5.8NIST NVDAV:N/AC:M/Au:N/C:P/I:N/A:P
7.1NIST NVDCVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:N/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)
Vectorlocal
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-125Out-of-bounds Read
T1204.002User Execution: Malicious 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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