Bug 2571448 (CVE-2026-97040)

Summary:	CVE-2026-97040 cmd/go: cmd/link: golang: golang: Arbitrary code execution via crafted .syso files
Product:	[Other] Security Response	Reporter:	OSIDB Bzimport <bzimport>
Component:	vulnerability	Assignee:	Product Security DevOps Team <prodsec-dev>
Status:	NEW ---	QA Contact:
Severity:	high	Docs Contact:
Priority:	high
Version:	unspecified	CC:	akhatavk, aos-team-art-private, asdas, cahl, crizzo, dfreiber, dpaolell, drow, dymurray, jburrell, jdelft, jupierce, kaycoth, lgarciaa, ljawale, mbiarnes, msilmser, ppalepu, ppostler, prdhamdh, rhel-process-autobot, sdawley, sghai, sidsharm, suppawar, vkumar, vlaad, watson-tool-maintainers
Target Milestone:	---	Keywords:	Security
Target Release:	---
Hardware:	All
OS:	Linux
Whiteboard:
Fixed In Version:		Doc Type:	---
Doc Text:	A flaw was found in Go. An attacker can achieve arbitrary code execution by supplying a Go package containing a crafted system object (.syso) file. The Go linker improperly parses these files as internal Go compiler objects instead of host objects, bypassing validation checks on linker flags. When the package is built, untrusted linker directives are passed to the external linker, allowing arbitrary commands or code to execute during the build process.	Story Points:	---
Clone Of:		Environment:
Last Closed:		Type:	---
Regression:	---	Mount Type:	---
Documentation:	---	CRM:
Verified Versions:		Category:	---
oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---	Target Upstream Version:
Embargoed:

Description OSIDB Bzimport 2026-11-11 03:21:44 UTC

Building a package containing a crafted ".syso" file could bypass cgo flag validation and inject arbitrary linker flags when linking. When loading ".syso" entries from a package archive, the linker only checked for recognized host object headers (ELF, Mach-O, PE, and XCOFF) before falling through to Go object parsing. A ".syso" file beginning with a "go object" header was parsed as a Go compiler object, allowing untrusted cgo metadata directives (such as "cgo_ldflag" or "cgo_dynamic_linker") embedded in the ".syso" file to be passed to the external linker without validation. Additionally, ".syso" filenames longer than 16 bytes lost their ".syso" extension when truncated in archive headers, and unrecognized ".syso" formats forced external linking in pure-Go builds. The linker now rejects ".syso" files that are not recognized host object formats, and "cmd/go" and "cmd/pack" preserve the ".syso" suffix when truncating long archive member names.