Bug 1790845 (CVE-2019-20352)

Summary:	CVE-2019-20352 nasm: heap-based buffer over-read in set_text_free when called from expand_one_smacro in asm/preproc.c
Product:	[Other] Security Response	Reporter:	Marian Rehak <mrehak>
Component:	vulnerability	Assignee:	Nobody <nobody>
Status:	NEW ---	QA Contact:
Severity:	low	Docs Contact:
Priority:	low
Version:	unspecified	CC:	contribs, dominik, fweimer, java-sig-commits, mizdebsk, nickc, pbonzini
Target Milestone:	---	Keywords:	Security
Target Release:	---
Hardware:	All
OS:	Linux
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oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---	Target Upstream Version:
Embargoed:
Bug Depends On:	1790847, 1791605, 1791606
Bug Blocks:	1790868

Description Marian Rehak 2020-01-14 11:46:37 UTC

In Netwide Assembler (NASM) 2.15rc0, a heap-based buffer over-read occurs (via a crafted .asm file) in set_text_free when called from expand_one_smacro in asm/preproc.c.

Upstream Issue:

https://bugzilla.nasm.us/show_bug.cgi?id=3392636

Comment 1 Marian Rehak 2020-01-14 11:47:40 UTC

Created nasm tracking bugs for this issue:

Affects: fedora-all [bug 1790847]

Comment 2 Huzaifa S. Sidhpurwala 2020-01-16 08:48:27 UTC

Nasm is an assembler/disassembler for Intel x86 architecture. This flaw can be triggered when nasm is used to assemble a malicious assembly instructions file. These operations are usually done by developers or users have local shell accounts. Also since this is an OOB read flaw, it can only cause a crash.