CVE-2018-19755

There is an illegal address access at asm/preproc.c (function: is_mmacro) in Netwide Assembler ...

5.5 MediumFix available

There is an illegal address access at asm/preproc.c (function: is_mmacro) in Netwide Assembler (NASM) 2.14rc16 that will cause a denial of service (out-of-bounds array access) because a certain conversion can result in a negative integer.

Attack profile

How easy it is to exploit

Attack vector: Local
Complexity: Low
Privileges needed: None
User interaction: Required

What an attacker can affect

Confidentiality: None
Integrity: None
Availability: High

Exploit likelihood

1.00%Up 0.2 points since Apr 14, 2021

What each source reports

NVD Score used 5.5

Record: CVE-2018-19755
CVSS 3.0: 5.5 MediumCVSS:3.0/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H
CVSS 2.0: 4.3 MediumAV:N/AC:M/Au:N/C:N/I:N/A:P
Weakness: CWE-20
Updated: 2026-11-02

CVE List No score

Record: CVE-2018-19755
Updated: 2026-11-02

EUVDEUVD-2018-11439 No score

Record: EUVD-2018-11439
Updated: 2026-11-03

GitHub AdvisoriesGHSA-cvx6-2fc8-p5cg 5.5

There is an illegal address access at asm/preproc.c (function: is_mmacro) in Netwide Assembler ...

Record: GHSA-cvx6-2fc8-p5cg
CVSS 3.0: 5.5 MediumCVSS:3.0/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H
Weakness: CWE-20
Updated: 2026-11-02

OSV 5.5

Record: CVE-2018-19755
CVSS 3.0: 5.5 MediumCVSS:3.0/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H
Updated: 2026-11-02

OSVDEBIAN-CVE-2018-19755 5.5

Record: DEBIAN-CVE-2018-19755
CVSS 3.0: 5.5 MediumCVSS:3.0/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H
Updated: 2026-11-02

OSVUBUNTU-CVE-2018-19755 5.5

Record: UBUNTU-CVE-2018-19755
CVSS 3.0: 5.5 MediumCVSS:3.0/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H
Updated: 2026-11-02

Affected products

nasm netwide assembler

Affected packages

Affected packages
Package	Affected	Fixed
`nasm` Debian:12	before 2.15.02-1	2.15.02-1
`nasm` Debian:13	before 2.15.02-1	2.15.02-1
`nasm` Debian:14	before 2.15.02-1	2.15.02-1
`nasm` Ubuntu:16.04:LTS	All versions, plus listed versions 2.11.06-1really2.11.05-12.11.08-12.11.08-1ubuntu0.1	None known
`nasm` Ubuntu:18.04:LTS	All versions, plus listed versions 2.13.01-22.13.02-0.1	None known
`nasm` Ubuntu:20.04:LTS	All versions, plus listed versions 2.14.02-1	None known

History

History
Recorded	Changed	Sources
Nov 3, 2026	aliases	EUVD
Nov 2, 2026	first indexed	CVE List, GitHub Advisories, NVD, OSV

Dates are when Every CVE recorded each change. Upstream dates may differ.

In short

CVE-2018-19755 is a medium vulnerability (CVSS 5.5) in Nasm Netwide Assembler, published November 30, 2018. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 1.00%, the 62nd percentile. Fixed in nasm 2.15.02-1.