Bug 1214531 (CVE-2020-21686)

Summary:	VUL-0: CVE-2020-21686: nasm: stack-use-after-scope issue in expand_mmac_params function in preproc.c
Product:	[Novell Products] SUSE Security Incidents	Reporter:	Alexander Bergmann <abergmann>
Component:	Incidents	Assignee:	Security Team bot <security-team>
Status:	RESOLVED WONTFIX	QA Contact:	Security Team bot <security-team>
Severity:	Minor
Priority:	P3 - Medium	CC:	abergmann, carlos.lopez, mvetter, security-team, stoyan.manolov
Version:	unspecified
Target Milestone:	---
Hardware:	Other
OS:	Other
URL:	https://smash.suse.de/issue/375968/
Whiteboard:	CVSSv3.1:SUSE:CVE-2020-21686:3.3:(AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:L)
Found By:	Security Response Team	Services Priority:
Business Priority:		Blocker:	---
Marketing QA Status:	---	IT Deployment:	---

Description Alexander Bergmann 2023-08-23 13:39:49 UTC

CVE-2020-21686

A stack-use-after-scope issue discovered in expand_mmac_params function in
preproc.c in nasm before 2.15.04 allows remote attackers to cause a denial of
service via crafted asm file.

No upstream fix available.

References:
http://web.nvd.nist.gov/view/vuln/detail?vulnId=CVE-2020-21686
https://www.cve.org/CVERecord?id=CVE-2020-21686
https://bugzilla.nasm.us/show_bug.cgi?id=3392643

Comment 1 Alexander Bergmann 2023-08-23 13:40:42 UTC

https://bugzilla.nasm.us/show_bug.cgi?id=3392643#c1

Doesn't trigger in nasm-2.15.04rc5-4-g51e23ac7

So it looks like the only affected code-streams are:

SUSE:SLE-12:Update
SUSE:SLE-15:Update

Comment 2 Alexander Bergmann 2023-08-23 13:40:47 UTC

Note: Do not trust data from unknown sources. Do not assemble/disassemble binaries from unknown sources without a sandbox environment that protects you from possible attacks.

In general: This is not a severe issue. It can only be exploited if general security measurements and best practices are not followed.

Comment 4 Michael Vetter 2023-09-20 08:07:38 UTC

Please see https://bugzilla.suse.com/show_bug.cgi?id=1214499#c4

Comment 5 Carlos López 2024-04-19 08:59:39 UTC

Closing as WONTFIX as discussed above.