CVE-2023-49557Public exploit

Assembler crash via null section dereference

Published Jan 2, 2024 · Updated Jun 18, 2025

NULL-pointer dereference in Yasm 1.3.0.86.g9def allows local users to crash the assembler by processing a crafted input file. During NASM expression parsing, parse_expr6 passes a null section pointer to yasm_section_bcs_first, which dereferences sect->bcs without validating the pointer. The user must run Yasm on the crafted file; the crash terminates that assembler process, and the project disputes any security consequence because it treats assembly inputs as trusted.

CVSS severity5.5
Medium
EPSS probability0.43%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

NULL-pointer dereference in Yasm 1.3.0.86.g9def allows local users to crash the assembler by processing a crafted input file. During NASM expression parsing, parse_expr6 passes a null section pointer to yasm_section_bcs_first, which dereferences sect->bcs without validating the pointer. The user must run Yasm on the crafted file; the crash terminates that assembler process, and the project disputes any security consequence because it treats assembly inputs as trusted.

The record

CVE
CVE-2023-49557
Published
Jan 2, 2024
Updated
Jun 18, 2025
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-400, T1203
Attack vector
local
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jan 2, 2024CVE publishedPublication date reported by the CVE source.
  2. Jun 18, 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

5.5Canonical UbuntuCVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H
5.0SUSECVSS:3.1/AV:L/AC:L/PR:L/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
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.

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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-400Uncontrolled Resource Consumption
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

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Your stack

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