Bug 2566211 (CVE-2026-63475)

Summary: CVE-2026-63475 isomorphic-git: isomorphic-git: Denial of Service via circular symbolic references
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
Status: NEW --- QA Contact:
Severity: medium Docs Contact:
Priority: medium    
Version: unspecifiedCC: 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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A flaw was found in isomorphic-git. This vulnerability allows a malicious or compromised remote server to cause a persistent Denial of Service (DoS). During a repository clone operation, the server can supply circular symbolic references that the client stores locally without cycle detection. Subsequent commands attempting to resolve these references enter an infinite loop, freezing the application and leaving the repository unusable.
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oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
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Description OSIDB Bzimport 2026-11-03 20:04:53 UTC 
isomorphic-git is a pure JavaScript implementation of Git for Node.js and browsers. Prior to 1.38.6, isomorphic-git persists server-supplied circular symref= capabilities through updateRemoteRefs, and GitRefManager.resolve() follows the resulting loose symbolic references without a default depth limit or cycle detection. After a clone from a malicious or man-in-the-middle-controlled remote, operations such as log, status, checkout, and branch that resolve refs/remotes/origin/a or refs/remotes/origin/b do not terminate. The circular references remain on disk, leaving the repository unusable for the application and causing a persistent denial of service. This issue is fixed in version 1.38.6.