CVE-2025-8842Public exploit

Local crash via freed directive structure

Published Aug 11, 2025 · Updated Aug 11, 2025

Use-after-free in NASM 2.17rc0 allows local users to crash the assembler by processing a malformed file with crafted preprocessor directives. The do_directive path reads four bytes from a directive structure after pp_tokline frees its 192-byte allocation during token processing. Triggering requires low-privileged local execution with the crafted file; the demonstrated consequence is an assembler-process abort, not a system-wide service interruption.

CVSS severity7.8
High
EPSS probability0.23%
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 NASM 2.17rc0 allows local users to crash the assembler by processing a malformed file with crafted preprocessor directives. The do_directive path reads four bytes from a directive structure after pp_tokline frees its 192-byte allocation during token processing. Triggering requires low-privileged local execution with the crafted file; the demonstrated consequence is an assembler-process abort, not a system-wide service interruption.

The record

CVE
CVE-2025-8842
Published
Aug 11, 2025
Updated
Aug 11, 2025
Vendor
NASM
Product
NASM
Classifications
CWE-416
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Aug 11, 2025CVE publishedPublication date reported by the CVE source.
  2. Aug 11, 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?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=2.17rc0

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

NASM · NASMversion=2.17rc0

Published CVSS scores

7.8NVDCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/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
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-416Use After Free

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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