CVE-2021-4021Public exploitNetwork attack vector

Analysis hang via oversized ELF segment mapping

Published Feb 24, 2022 · Updated Aug 3, 2024

Uncontrolled resource consumption in radare2 allows remote attackers to hang binary analysis via a crafted ELF64 MIPS file. The ELF loader trusts a PT_LOAD p_memsz value of UINT64_MAX and maps the resulting zero-filled region for instruction analysis. The hang occurs only when an affected build performs full analysis on the file, leaving the analysis process unresponsive without reported data exposure or modification.

CVSS severity7.5
High
EPSS probability1.05%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Uncontrolled resource consumption in radare2 allows remote attackers to hang binary analysis via a crafted ELF64 MIPS file. The ELF loader trusts a PT_LOAD p_memsz value of UINT64_MAX and maps the resulting zero-filled region for instruction analysis. The hang occurs only when an affected build performs full analysis on the file, leaving the analysis process unresponsive without reported data exposure or modification.

The record

CVE
CVE-2021-4021
Published
Feb 24, 2022
Updated
Aug 3, 2024
Vendor
radareorg
Product
radare2
Classifications
CWE-400, CWE-834, T1499
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Feb 24, 2022CVE 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

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=radare2 5.6.2, radare2 5.6.0, radare2 5.5.4 and radare2 5.5.2

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

radareorg · radare2version=radare2 5.6.2, radare2 5.6.0, radare2 5.5.4 and radare2 5.5.2

Published CVSS scores

5.0NIST NVDAV:N/AC:L/Au:N/C:N/I:N/A:P
7.5NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
7.5Canonical UbuntuCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/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)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-400Uncontrolled Resource Consumption
CWE-834Excessive Iteration
T1499Endpoint Denial of Service

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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