CVE-2023-49556Public exploit

Assembler crash via out-of-bounds expression read

Published Jan 2, 2024 · Updated Jun 3, 2025

Heap buffer overflow in Yasm 1.3.0.86.g9def allows context-dependent attackers to crash the assembler with a crafted input file. The expr_delete_term function reads a four-byte term field immediately beyond a 56-byte heap allocation while simplifying the crafted expression tree. A user must invoke Yasm on the file; the demonstrated consequence is a process crash, with no shown confidentiality or integrity impact.

CVSS severity5.5
Medium
EPSS probability0.42%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
Coverage for this vulnerability

See if you're affected

Explore vulnerability checks for your environment with Hinoki.

Book a demo

Summary

What happened

Heap buffer overflow in Yasm 1.3.0.86.g9def allows context-dependent attackers to crash the assembler with a crafted input file. The expr_delete_term function reads a four-byte term field immediately beyond a 56-byte heap allocation while simplifying the crafted expression tree. A user must invoke Yasm on the file; the demonstrated consequence is a process crash, with no shown confidentiality or integrity impact.

The record

CVE
CVE-2023-49556
Published
Jan 2, 2024
Updated
Jun 3, 2025
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-120, T1203
Attack vector
local
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jan 2, 2024CVE publishedPublication date reported by the CVE source.
  2. Jun 3, 2025Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

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

5.5CISA-ADPCVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H
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 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-120Buffer Copy without Checking Size of Input ('Classic Buffer Overflow')
T1203Exploitation for Client Execution

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

See the directory against your own environment.

Your stack

Check the software in your environment

Book a demo to see how Hinoki identifies affected software and validates exploitability in your environment.

Book a demo