Bug 2490544 (CVE-2026-55392)

Summary: CVE-2026-55392 nilfs-utils: NILFS utilities: Denial of Service via crafted NILFS2 images
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security <prodsec-ir-bot>
Status: NEW --- QA Contact:
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Priority: medium    
Version: unspecifiedKeywords: Security
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Hardware: All   
OS: Linux   
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A flaw was found in NILFS utilities. An attacker can exploit this vulnerability by supplying a crafted NILFS2 image. This can lead to undefined behavior, oversized shifts, or out-of-memory conditions, ultimately causing a Denial of Service (DoS) by crashing tools such as nilfs-tune and dumpseg.
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oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
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Bug Depends On: 2491296, 2491298    
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Description OSIDB Bzimport 2026-06-18 19:01:19 UTC
NILFS utilities through 2.3.0, fixed in commit 26efb5d, nilfs_sb_is_valid() function fails to validate s_log_block_size field in NILFS2 superblock before bit-shift operations. Attackers supplying crafted NILFS2 images trigger undefined behavior through oversized shifts or out-of-memory conditions, crashing tools like nilfs-tune and dumpseg.