CVE-2023-29420Public exploitNetwork attack vector

Decompression crash via unchecked block length

Published Apr 6, 2023 · Updated Mar 5, 2025

Memory-safety flaw in bzip3 before 1.2.3 allows context-dependent attackers to crash decompression with a crafted archive. bz3_decode_block subtracts eight from an unchecked short block length and passes the negative result to memmove as an oversized copy length. Exploitation requires processing attacker-supplied compressed data and interrupts the process performing decompression.

CVSS severity6.5
Medium
EPSS probability0.89%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Memory-safety flaw in bzip3 before 1.2.3 allows context-dependent attackers to crash decompression with a crafted archive. bz3_decode_block subtracts eight from an unchecked short block length and passes the negative result to memmove as an oversized copy length. Exploitation requires processing attacker-supplied compressed data and interrupts the process performing decompression.

The record

CVE
CVE-2023-29420
Published
Apr 6, 2023
Updated
Mar 5, 2025
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-119, T1499.004
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Apr 6, 2023CVE publishedPublication date reported by the CVE source.
  2. Mar 5, 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?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

6.5CISA-ADPCVSS:3.1/AV:N/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)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-119Improper Restriction of Operations within the Bounds of a Memory Buffer
T1499.004Application or System Exploitation Flood

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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