CVE-2021-29425Network attack vector

Limited path traversal via incomplete normalization

Published Apr 13, 2021 · Updated Aug 3, 2024

Path traversal in Apache Commons IO 2.2 through 2.6 allows attackers to reach parent-directory files through crafted paths. FilenameUtils.normalize returns crafted paths such as //../foo or ..\foo unchanged instead of rejecting or resolving the leading parent segment. Impact occurs only when calling code uses attacker-controlled normalized output to construct a filesystem path and is limited to one parent directory.

CVSS severity4.8
Medium
EPSS probability10.23%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Path traversal in Apache Commons IO 2.2 through 2.6 allows attackers to reach parent-directory files through crafted paths. FilenameUtils.normalize returns crafted paths such as //../foo or ..\foo unchanged instead of rejecting or resolving the leading parent segment. Impact occurs only when calling code uses attacker-controlled normalized output to construct a filesystem path and is limited to one parent directory.

The record

CVE
CVE-2021-29425
Published
Apr 13, 2021
Updated
Aug 3, 2024
Vendor
The Apache Software Foundation
Product
Apache Commons IO
Classifications
CWE-20, CWE-22
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Apr 13, 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=Apache Commons IO 2.2
  2. Affected versionversion=Apache Commons IO 2.3
  3. Affected versionversion=Apache Commons IO 2.4
  4. Affected versionversion=Apache Commons IO 2.5
  5. Affected versionversion=Apache Commons IO 2.6

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

The Apache Software Foundation · Apache Commons IOversion=Apache Commons IO 2.2; version=Apache Commons IO 2.3; version=Apache Commons IO 2.4; version=Apache Commons IO 2.5; version=Apache Commons IO 2.6

Published CVSS scores

4.8NIST National Vulnerability DatabaseCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/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 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-20Improper Input Validation
CWE-22Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')

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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