Bug 2566217 (CVE-2026-63478)

Summary:	CVE-2026-63478 isomorphic-git: isomorphic-git: Arbitrary file write via directory traversal
Product:	[Other] Security Response	Reporter:	OSIDB Bzimport <bzimport>
Component:	vulnerability	Assignee:	Product Security DevOps Team <prodsec-dev>
Status:	NEW ---	QA Contact:
Severity:	medium	Docs Contact:
Priority:	medium
Version:	unspecified	CC:	abarbaro, alizardo, dhanak, drosa, dschmidt, dsimansk, ikhan, jchui, jhe, jlanda, kingland, kshier, ktsao, mnovotny, nboldt, oaljalju, psrna, rbobbitt, sausingh, simaishi, stcannon, yguenane
Target Milestone:	---	Keywords:	Security
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Hardware:	All
OS:	Linux
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Doc Text:	A flaw was found in isomorphic-git. A remote attacker controlling a malicious repository or intercepting network traffic can exploit improper path validation during clone or checkout operations by supplying directory traversal sequences in repository tree entries. This issue allows the attacker to write arbitrary files outside the working directory on the host file system, which may lead to arbitrary code execution.	Story Points:	---
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oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---	Target Upstream Version:
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Description OSIDB Bzimport 2026-11-03 20:05:31 UTC

isomorphic-git is a pure JavaScript implementation of Git for Node.js and browsers. Prior to 1.38.6, isomorphic-git's tree parser in src/models/GitTree.js accepts a standalone .. tree-entry name because it rejects only path separators. During clone or checkout from a malicious or man-in-the-middle-controlled non-GitHub remote, nested .. entries can escape the working-tree root and write files at attacker-selected parent paths on any host-backed fs provider. The arbitrary file write can overwrite startup or configuration files and lead to code execution. GitHub-hosted trees are not a direct source because GitHub rejects .. entries during repository integrity checks. This issue is fixed in version 1.38.6.