CVE-2023-23457Public exploit

Process crash via out-of-bounds error formatting

Published Jan 12, 2023 · Updated Apr 7, 2025

Improper bounds handling in UPX 4.0.1 allows attackers to crash the packer through a crafted 64-bit Linux ELF file. When an ELF dynamic offset lies beyond EOF, PackLinuxElf64::invert_pt_dynamic reads dt_names[k] out of bounds while formatting the rejection message. A victim must run UPX on the crafted file; the resulting invalid memory access terminates the UPX process.

CVSS severity5.3
Medium
EPSS probability0.35%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Improper bounds handling in UPX 4.0.1 allows attackers to crash the packer through a crafted 64-bit Linux ELF file. When an ELF dynamic offset lies beyond EOF, PackLinuxElf64::invert_pt_dynamic reads dt_names[k] out of bounds while formatting the rejection message. A victim must run UPX on the crafted file; the resulting invalid memory access terminates the UPX process.

The record

CVE
CVE-2023-23457
Published
Jan 12, 2023
Updated
Apr 7, 2025
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-119, T1204.002
Attack vector
local
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jan 12, 2023CVE publishedPublication date reported by the CVE source.
  2. Apr 7, 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 vectorlocal
Required privilegesunauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

5.3Fedora ProjectCVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:L
5.5NIST NVDCVSS: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.

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)
Vectorlocal
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-119Improper Restriction of Operations within the Bounds of a Memory Buffer
T1204.002User Execution: Malicious 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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