CVE-2021-33451Public exploit

Denial of service via crafted-file memory leak

Published Jul 26, 2022 · Updated Aug 3, 2024

Memory leak in fill_buffer() in lrzip 0.641 allows local users to cause denial of service by supplying a crafted archive. While testing the archive, fill_buffer() allocates a 24-byte object that remains unreleased after decompression fails. Opening or testing the crafted file is required, and the demonstrated consequence is unreleased process memory rather than code execution or data access.

CVSS severity5.5
Medium
EPSS probability0.31%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Memory leak in fill_buffer() in lrzip 0.641 allows local users to cause denial of service by supplying a crafted archive. While testing the archive, fill_buffer() allocates a 24-byte object that remains unreleased after decompression fails. Opening or testing the crafted file is required, and the demonstrated consequence is unreleased process memory rather than code execution or data access.

The record

CVE
CVE-2021-33451
Published
Jul 26, 2022
Updated
Aug 3, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-401, T1499.004, T1204.002
Attack vector
local
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jul 26, 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

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Is a vulnerable build present?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectorlocal
Required privilegesunauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

5.5NVDCVSS:3.1/AV:L/AC:L/PR:N/UI:R/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)
Vectorlocal
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-401Missing Release of Memory after Effective Lifetime
T1499.004Application or System Exploitation
T1204.002Malicious 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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