Local denial of service via f2fs race
Published Sep 16, 2026 · Updated Sep 16, 2026
Race condition in Linux 4.7 allows local users to hang f2fs fsync processing during concurrent file truncation. In f2fs_fsync_node_pages(), a retained last_folio can lose its mapping while f2fs_truncate invalidates pages, causing is_node_folio() to remain false and the retry condition to remain true. Exploitation requires concurrent fsync and truncation against an f2fs file and can leave the kernel path spinning indefinitely, interrupting filesystem service.
Summary
What happened
Race condition in Linux 4.7 allows local users to hang f2fs fsync processing during concurrent file truncation. In f2fs_fsync_node_pages(), a retained last_folio can lose its mapping while f2fs_truncate invalidates pages, causing is_node_folio() to remain false and the retry condition to remain true. Exploitation requires concurrent fsync and truncation against an f2fs file and can leave the kernel path spinning indefinitely, interrupting filesystem service.
The record
- CVE
- CVE-2026-89833
- Published
- Sep 16, 2026
- Updated
- Sep 16, 2026
- Vendor
- The Linux Kernel Organization
- Product
- Linux
- Classifications
- T1499.004
- Attack vector
- local
- Privileges
- Unavailable
Timeline
How it unfolded
- Sep 16, 2026CVE publishedPublication date reported by the CVE source.
- Sep 16, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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- Affected versionversion=4.7
- Affected versionversion=608514deba38c8611ad330d6a3c8e2b9a1f68e4b <161513f53e4ac90fd356433bdf8e31e6adeb92af
- Affected versionversion=608514deba38c8611ad330d6a3c8e2b9a1f68e4b <905411f6504876d268ba8dafc8e75367782da4b7
- Affected versionversion=608514deba38c8611ad330d6a3c8e2b9a1f68e4b <ce366bfa821ec81dd45bde547ee31e659306cc61
What conditions does exploitation require?
What is affected?
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Attacks
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Technologies
Your stack
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