CVE-2020-18780

Publication date 22 August 2023

Last updated 15 September 2025

Ubuntu priority

Cvss 3 Severity Score

Description

A Use After Free vulnerability in function new_Token in asm/preproc.c in nasm 2.14.02 allows attackers to cause a denial of service via crafted nasm command.

Read the notes from the security team

Why is this CVE low priority?

ej7367> Crash in CLI tool - minimal security impact.

Learn more about Ubuntu priority

Status

Show unmaintained releases

Package	Ubuntu Release	Status
nasm	25.04 plucky	Not affected
	24.10 oracular	Ignored end of life, was needs-triage
	24.04 LTS noble	Not affected
	23.10 mantic	Ignored end of life, was needs-triage
	23.04 lunar	Ignored end of life, was needs-triage
	22.04 LTS jammy	Not affected
	20.04 LTS focal	Ignored changes too intrusive
	18.04 LTS bionic	Ignored changes too intrusive
	16.04 LTS xenial	Ignored changes too intrusive
	14.04 LTS trusty	Ignored end of standard support

Notes

ej7367

Upstream commit 41e9682efed7cd1df133b1b4ac806e07723f1486 introduced significant changes to asm/preproc.c in 2.15.x, which makes it too intrusive to backport the fix to Ubuntu 20.04 LTS and older.

Patch details

For informational purposes only. We recommend not to cherry-pick updates. How can I get the fixes?

Package	Patch details
nasm	Upstream: 7c88289

Severity score breakdown

Parameter	Value
Base score	5.5 · Medium
Attack vector	Local
Attack complexity	Low
Privileges required	None
User interaction	Required
Scope	Unchanged
Confidentiality	None
Integrity impact	None
Availability impact	High
Vector	CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H