Bug 2541268 (CVE-2026-98005)

Summary: CVE-2026-98005 kernel: erofs: delimit inode_share cache key components
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: akhatavk, aos-team-art-private, asdas, dpaolell, jdelft, jupierce, lgarciaa, mbiarnes, ppalepu, ppostler, prdhamdh, rhel-process-autobot, sghai, sidsharm, suppawar, vlaad, watson-tool-maintainers
Target Milestone: ---Keywords: Security
Target Release: ---   
Hardware: All   
OS: Linux   
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A flaw was found in the Linux kernel's EROFS (Enhanced Read-Only File System) component. Due to a missing delimiter between the domain identifier and fingerprint when generating cache keys for shared inodes, the resulting cache entries are ambiguous. A local user could exploit this ambiguity to cause cache key collisions, which may lead to improper inode sharing or unauthorized data access across domains.
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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 2026-09-25 11:13:10 UTC 
In the Linux kernel, the following vulnerability has been resolved:

erofs: delimit inode_share cache key components

Previously, inode_share keys were encoded as follows:

  fingerprint || domain_id

It would be better to have a separator between the fingerprint and domain
ID so that the fingerprint won't be parsed as part of a domain ID.

Change the key encoding as follows:

  domain_id || '\0' || fingerprint

Since domain_id is a NUL-terminated string, this makes the in-memory key
indices unambiguous.
Comment 1 Keith Grant 2026-09-28 18:55:27 UTC 
Upstream advisory:
https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-98005.mbox