CVE-2023-31974Public exploit

Assembler crash via stale macro pointer dereference

Published May 9, 2023 · Updated Jan 28, 2025

Use-after-free in Yasm 1.3.0 allows local users to crash the assembler by processing a crafted assembly source file. The NASM preprocessor frees a macro object in pp_getline, then the error function reads a field through the stale pointer, producing an AddressSanitizer abort. The trigger requires processing attacker-controlled source, and the Yasm project disputes security impact because its policy treats assembler inputs as trusted.

CVSS severity5.5
Medium
EPSS probability0.29%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Use-after-free in Yasm 1.3.0 allows local users to crash the assembler by processing a crafted assembly source file. The NASM preprocessor frees a macro object in pp_getline, then the error function reads a field through the stale pointer, producing an AddressSanitizer abort. The trigger requires processing attacker-controlled source, and the Yasm project disputes security impact because its policy treats assembler inputs as trusted.

The record

CVE
CVE-2023-31974
Published
May 9, 2023
Updated
Jan 28, 2025
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-416, T1204.002
Attack vector
local
Privileges
unauthenticated

Timeline

How it unfolded

  1. May 9, 2023CVE publishedPublication date reported by the CVE source.
  2. Jan 28, 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

5.5NIST NVDCVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H
5.5CISA-ADPCVSS: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-416Use After Free
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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