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Nasm EUVDEUVD-2026-21382

| CVE-2026-6069 HIGH
Out-of-bounds Write (CWE-787)
2026-04-10 certcc
Buffer Overflow Memory Corruption Red Hat Suse Nasm
7.5
CVSS 3.1 · NVD
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Attack ChainAIDerived

Hypothetical attack flow derived from CVE metadata – not a confirmed exploit chain

  1. Access
    Provide malformed binary to NASM disassembler
  2. Delivery
    Trigger disasm() with oversized slen parameter
  3. Exploit
    Exceed buffer capacity in formatting function
  4. Execution
    Cause stack-based buffer overflow
  5. Impact
    Denial of service via application crash

Vulnerability Assessment

Weakness
CWE
CWE-787
ASVS 5.0
V15 - Secure Coding and Architecture Bounds checking, write limits
MITRE ATT&CK

2 techniques across 2 tactics: Execution, Privilege Escalation

The technique list with ATT&CK links and the kill-chain view is part of the Basic plan and up.

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Exploitation Conditions

The attacker must provide a malformed or crafted binary file to a system running NASM that processes it with the disasm() function. No authentication required. The vulnerability triggers automatically during disassembly formatting when slen exceeds buffer capacity.
Impact

Network-accessible stack buffer overflow with unauthenticated trigger and high availability impact (CVSS 7.5). NASM disasm() function exploitation requires malformed assembly input; automatable delivery via network vector increases real-world blast radius. Moderate observed exploitation activity suggests active reconnaissance, warranting prioritization for patching NASM deployments in build pipelines and code analysis toolchains.
Exploit ScenarioDerived

Attacker sends crafted assembly code to NASM disassembler (network-accessible service or batch processor) with oversized formatting directives. Malformed slen parameter triggers stack buffer overflow in disasm() output formatting, causing denial of service or memory corruption on the host system.
This Week Schedule remediation this week. Why: HIGH severity (CVSS 7.0-8.9).
Patch available 0.0% exploitation probability (EPSS)

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AnalysisAIv1 – Apr 10, 2026

Stack-based buffer overflow in NASM's disasm() function enables unauthenticated denial-of-service when processing malicious assembly input. Attacker-controlled disassembly formatting triggers out-of-bounds write when string length exceeds buffer capacity, causing application crash. Affects NASM assembler version 3.02rc5. Publicly available exploit code exists. CVSS 7.5 (High) reflects network-accessible attack vector requiring no privileges or user interaction, with availability impact only.

RemediationAI

Upstream fix available (PR/commit); released patched version not independently confirmed. Monitor vendor repository at https://github.com/netwide-assembler/nasm/issues/217 for definitive patch release addressing buffer overflow in disasm() function. Until patched version confirmed, avoid processing untrusted assembly input with disassembly functionality. Implement input validation limiting slen to safe buffer boundaries. Deploy network-level controls restricting NASM exposure to untrusted sources given unauthenticated remote attack vector. For production environments, defer NASM upgrade to stable release post-3.02rc5 incorporating buffer overflow remediation. Consult NVD advisory https://nvd.nist.gov/vuln/detail/CVE-2026-6069 for vendor updates. Given proof-of-concept code exists, prioritize patch deployment upon availability to mitigate denial-of-service risk.

Affected VersionsENISA

nasm nasm-3.02rc5

Affects your stack

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Technical ContextAI · show details

Buffer overflow occurs in disasm() during disassembly output formatting when slen parameter exceeds allocated stack buffer size. Stack-based memory corruption allows attacker-controlled write beyond buffer boundaries. CVSS vector AV:N/AC:L/PR:N indicates remotely triggerable without authentication. No confidentiality or integrity impact (C:N/I:N), availability destruction only (A:H). SSVC confirms proof-of-concept availability and automatable exploitation with partial technical impact.

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Severity by source

NVD PRIMARY 7.5 HIGH
AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
SUSE HIGH
Red Hat 9.4 HIGH

Primary rating from NVD.

CVSS VectorNVD

Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High

DescriptionCVE.org

NASM’s disasm() function contains a stack based buffer overflow when formatting disassembly output, allowing an attacker triggered out-of-bounds write when slen exceeds the buffer capacity.

Executive ViewAI

Why It Matters

NASM assembler version 3.02rc5 contains a stack-based buffer overflow in the disasm() function that allows unauthenticated attackers to crash applications processing malicious assembly files, disrupting development and build pipelines. Organizations using NASM for code compilation or assembly processing face service availability risks with no vendor patch currently available.

Business Impact: High
Compensating Controls

No vendor-released patch identified at time of analysis. Interim mitigations: (1) Restrict NASM input processing to pre-validated, trusted assembly source files only; (2) Implement sandboxing or containerization of NASM processes to isolate crash impact; (3) Disable network-accessible NASM services and enforce local-only processing; (4) Downgrade to NASM 2.15.05 or earlier stable version if operationally feasible.

Threat Intelligence Overview

EPSS Score
0.0%
Top 88% exploitable
Social Media
1
Sightings
Data Quality
6 sources
Confidence: High
EUVD NVD CVE.org EPSS Vulnrichment Vendor CIRCL GitHub VulDB

How this decision was reached

The engine reads each signal below and applies a fixed list of rules from top to bottom. The first rule that matches sets the recommended action – like a statement, every line is shown.

SignalValue
Severity HIGH
CISA KEV No
Public POC No
EPSS 0.0%
Patch available Yes
Active threat No
Deciding rule
HIGH severity (CVSS 7.0-8.9)
What every action level means
Emergency Immediate action required. Criteria: CRITICAL + in CISA KEV (actively exploited) without patch, OR CRITICAL + EPSS > 30% without patch, OR CRITICAL + active threat signals without patch.
Act Now Prioritize within 24-48h. Criteria: in KEV with patch available, OR CRITICAL + public POC, OR HIGH + EPSS > 10%, OR CRITICAL + active threat, OR any CRITICAL severity.
This Week Schedule remediation this week. Criteria: HIGH severity (CVSS 7.0-8.9). Patch within normal change window.
This Month Plan within 30 days. Criteria: MEDIUM severity (CVSS 4.0-6.9), lower exploitation probability. Include in regular patch cycle.
Monitor Track and reassess. Criteria: LOW severity (CVSS 0.1-3.9), minimal exploitation risk. No immediate action needed.

SSVC AssessmentENISA

SSVC Decision
Out-of-Cycle
Exploitation
Poc
System Exposure· derived
Open
Automatable
Yes
Human Impact
High
Technical Impact
Partial

Priority Score

38
Low Medium High Critical
KEV: 0
EPSS: 0
CVSS: +38
PoC: 0
Weaponized: 0
Threat intel: 0
Gov advisory: 0

Attack Technique

Buffer Overflow HIGH

A buffer overflow occurs when a program writes more data to a memory buffer than it was allocated to hold, causing the excess data to spill into adjacent memory regions.

Memory Corruption HIGH

Memory corruption occurs when a program writes data beyond the boundaries of allocated memory regions or accesses memory in unintended ways, violating the integrity of the process's address space.

Related Vulnerabilities in NASM Buffer Overflow and Memory Corruption

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CVE-2026-6067 MEDIUM
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CVE-2026-6068 CRITICAL
9.6

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In NASM 2.15.04rc3, there is a double-free vulnerability in pp_tokline asm/preproc.c. Rated critical severity (CVSS 9.8)
CVE-2017-10686 HIGH POC
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In Netwide Assembler (NASM) 2.14rc0, there are multiple heap use after free vulnerabilities in the tool nasm. Rated high
CVE-2023-31722 HIGH POC
7.8 May 17

There exists a heap buffer overflow in nasm 2.16.02rc1 (GitHub commit: b952891). Rated high severity (CVSS 7.8), this vu
CVE-2019-8343 HIGH POC
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In Netwide Assembler (NASM) 2.14.02, there is a use-after-free in paste_tokens in asm/preproc.c. Rated high severity (CV
CVE-2018-19216 HIGH POC
7.8 Nov 12

Netwide Assembler (NASM) before 2.13.02 has a use-after-free in detoken at asm/preproc.c. Rated high severity (CVSS 7.8)
CVE-2018-19215 HIGH POC
7.8 Nov 12

Netwide Assembler (NASM) 2.14rc16 has a heap-based buffer over-read in expand_mmac_params in asm/preproc.c for the speci
CVE-2018-19214 HIGH POC
7.8 Nov 12

Netwide Assembler (NASM) 2.14rc15 has a heap-based buffer over-read in expand_mmac_params in asm/preproc.c for insuffici
CVE-2018-10254 HIGH POC
7.8 Apr 21

Netwide Assembler (NASM) 2.13 has a stack-based buffer over-read in the disasm function of the disasm/disasm.c file. Rat
CVE-2017-17818 HIGH POC
7.5 Dec 21

In Netwide Assembler (NASM) 2.14rc0, there is a heap-based buffer over-read that will cause a remote denial of service a
CVE-2017-17819 MEDIUM POC
5.5 Dec 21

In Netwide Assembler (NASM) 2.14rc0, there is an illegal address access in the function find_cc() in asm/preproc.c that

CVE-2017-17815 MEDIUM POC
5.5 Dec 21

In Netwide Assembler (NASM) 2.14rc0, there is an illegal address access in is_mmacro() in asm/preproc.c that will cause

Same weakness CWE-787 – Out-of-bounds Write

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CVE-2015-3113 CRITICAL POC
9.8
CVE-2011-2462 CRITICAL POC
9.8
CVE-2012-1889 HIGH POC
8.8
CVE-2010-3333 HIGH POC
7.8
CVE-2014-1761 HIGH POC
7.8
CVE-2009-3129 HIGH POC
7.8
CVE-2021-1732 HIGH POC
7.8
CVE-2013-3346 CRITICAL POC
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Same technique Buffer Overflow

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CVE-2017-7269 CRITICAL POC
9.8
CVE-2015-5119 CRITICAL POC
9.8
CVE-2020-0796 CRITICAL POC
10.0
CVE-2019-11043 CRITICAL POC
9.8
CVE-2009-0927 HIGH POC
8.8

Vendor StatusVendor

SUSE

Severity: High
Product Status
SUSE Linux Enterprise Desktop 15 SP7 Fixed
SUSE Linux Enterprise High Performance Computing 15 SP7 Fixed
SUSE Linux Enterprise Module for Development Tools 15 SP7 Fixed
SUSE Linux Enterprise Server 15 SP7 Fixed
SUSE Linux Enterprise Server for SAP Applications 15 SP7 Fixed

References

Advisories & patches
ADVISORY https://nvd.nist.gov/vuln/detail/CVE-2026-6069 ADVISORY https://vuldb.com/vuln/356818 REF https://github.com/netwide-assembler/nasm/issues/217

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