CVE-2021-36090Network attack vector

Service crash via unchecked ZIP symlink length

Published Jul 13, 2021 · Updated Aug 4, 2024

Improper length validation in Apache Commons Compress 1.0 through 1.20 allows attackers to crash ZIP-processing services with a crafted archive. AsiExtraField.parseFromLocalFileData allocates a symbolic-link byte array from an untrusted ZIP extra-field length before checking it against the available data. Any application that accepts and parses attacker-controlled ZIP archives can exhaust JVM memory and terminate its service process.

CVSS severity7.5
High
EPSS probability12.95%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Improper length validation in Apache Commons Compress 1.0 through 1.20 allows attackers to crash ZIP-processing services with a crafted archive. AsiExtraField.parseFromLocalFileData allocates a symbolic-link byte array from an untrusted ZIP extra-field length before checking it against the available data. Any application that accepts and parses attacker-controlled ZIP archives can exhaust JVM memory and terminate its service process.

The record

CVE
CVE-2021-36090
Published
Jul 13, 2021
Updated
Aug 4, 2024
Vendor
The Apache Software Foundation
Product
Apache Commons Compress
Classifications
CWE-130, T1499
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jul 13, 2021CVE 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?

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

  1. Affected versionversion=Apache Commons Compress <=1.20

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

The Apache Software Foundation · Apache Commons Compressversion=Apache Commons Compress <=1.20

Published CVSS scores

7.5NIST NVDCVSS: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.

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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-130Improper Handling of Length Parameter Inconsistency
T1499Endpoint Denial of Service

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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