CVE-2021-4287Network attack vector

File disclosure via unsanitized extracted symlinks

Published Dec 27, 2022 · Updated Apr 11, 2025

Symlink following in ReFirm Labs Binwalk 2.3.2 and earlier allows attackers to read files outside extraction output via a crafted archive. Extractor.callback accepts links created by external extraction utilities without checking whether their resolved targets escape the extraction directory, so later utilities can follow them. Exploitation requires a user to extract attacker-supplied content; NVD bounds the impact to confidentiality, while Debian disputes the CVE classification.

CVSS severity6.5
Medium
EPSS probability1.95%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Symlink following in ReFirm Labs Binwalk 2.3.2 and earlier allows attackers to read files outside extraction output via a crafted archive. Extractor.callback accepts links created by external extraction utilities without checking whether their resolved targets escape the extraction directory, so later utilities can follow them. Exploitation requires a user to extract attacker-supplied content; NVD bounds the impact to confidentiality, while Debian disputes the CVE classification.

The record

CVE
CVE-2021-4287
Published
Dec 27, 2022
Updated
Apr 11, 2025
Vendor
ReFirm Labs
Product
Binwalk
Classifications
CWE-59, CWE-61, T1204.002
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Dec 27, 2022CVE publishedPublication date reported by the CVE source.
  2. Apr 11, 2025Record 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=2.3.0
  2. Affected versionversion=2.3.1
  3. Affected versionversion=2.3.2

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

ReFirm Labs · Binwalkversion=2.3.0; version=2.3.1; version=2.3.2

Published CVSS scores

5.0VulDBCVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:L/I:L/A:L
6.5GitHubCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N
6.5NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N

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 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-59Improper Link Resolution Before File Access ('Link Following')
CWE-61UNIX Symbolic Link (Symlink) Following
T1204.002User Execution: Malicious File

Public exploit references

No public exploit references are available in this record.

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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