Bug 2559555 (CVE-2026-98879)

Summary: CVE-2026-98879 kernel: isofs: handle set_blocksize failures
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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Fixed In Version: Doc Type: ---
Doc Text:
A flaw was found in the Linux kernel's ISO 9660 (isofs) file system driver. The driver fails to handle errors when setting the storage block size during mount operations. A local user could exploit this flaw by mounting a specially crafted disk image with an invalid block size, triggering a kernel panic and leading to a Denial of Service (DoS).
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Last Closed: Type: ---
Regression: --- Mount Type: ---
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oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: --- Target Upstream Version:
Embargoed:

Description OSIDB Bzimport 2026-10-23 11:56:25 UTC
In the Linux kernel, the following vulnerability has been resolved:

isofs: handle set_blocksize failures

isofs uses buffer_heads, which don't handle block size > PAGE_SIZE well.
Without this, mounting we will hit the

        BUG_ON(offset >= folio_size(folio));

in folio_set_bh on the first __bread_gfp call.