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Mallory
High

Linux kernel XFS undersized l_iclog_roundoff log corruption vulnerability

IdentifiersCVE-2026-43365CWE-1284

CVE-2026-43365 is a vulnerability in the Linux kernel's XFS filesystem code caused by incorrect handling of the in-core log roundoff value (l_iclog_roundoff). When the XFS superblock does not specify a log stripe unit, the kernel can set the roundoff value to 512 bytes even when the log sector size is 4096 bytes. On affected filesystems, particularly those using 4K physical sectors, this mismatch can result in torn-write CRC failures, corrupted XFS journal/log state, and subsequent log recovery or mount failures. The issue is described by the upstream fix as "xfs: fix undersized l_iclog_roundoff values." The provided diagnostic output shows CRC failure detection in the log, inability to locate the log tail, and log mount/recovery failure with error -74. The content also notes that malformed filesystems can be produced by a broken mkfs in current xfsprogs for-next, and that a fuzzed on-disk superblock can also trigger the unsafe condition.

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ANALYST BRIEF

Impact, mitigation & remediation

What it means. What to do now. Patch path, mitigations, and the assume-compromise checklist.

Impact

What an attacker gets, and what they’ve been doing with it.

Successful triggering of this flaw can corrupt the XFS log and render the filesystem unmountable or unable to recover its journal during mount. The primary security impact is high availability loss, with limited integrity impact due to log corruption. The supplied CVSS vectors reflect no confidentiality impact, low integrity impact, and high availability impact.

Mitigation

If you can’t patch tonight, do this now.

Until patched kernels and corrected filesystem creation tools are deployed, reduce exposure by avoiding creation or use of XFS filesystems with inconsistent log geometry, especially on storage with 4K physical sectors where the superblock log stripe unit is absent or malformed. Validate XFS superblock and log parameters on newly created filesystems, and avoid mounting or trusting malformed or fuzzed XFS images from untrusted sources. If operationally feasible, restrict use of affected XFS volumes until updated kernels are installed.

Remediation

Patch, then assume compromise.

Apply a Linux kernel update containing the upstream XFS fix for undersized l_iclog_roundoff handling. Vendor guidance in the provided content indicates that SUSE has shipped fixes in multiple kernel update advisories across affected product lines. Where applicable, also use corrected xfsprogs/mkfs tooling so that newly created filesystems do not inherit the broken on-disk configuration described in the content.
PUBLIC EXPLOITS

Exploits

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VALID 0 / 0 TOTALView more in app

No public exploit code observed for this vulnerability.

EXPOSURE SURFACE

Affected products & vendors

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VendorProductType
LinuxLinux Kerneloperating_system

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ACTIVITY FEED

Recent activity

5 sources tracked across advisories and community write-ups. News coverage will land here when it surfaces.

No news coverage yet. Advisories and community discussion only.

What this page doesn’t show

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Exposure mapping

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Threat actor evidence

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Associated malware

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Detection signatures

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Vendor-by-vendor mapping

Cross-references every affected SKU, including bundled OEM variants.

Social activity1

Community discussion across Reddit, Mastodon, and other social sources.