CVE Catalog

CVE-2026-53165

HighCVSS 7.5
Published: Updated: Translated: NVD NIST

Exploitation Probability (EPSS)

Low risk
0.36%

28th percentile - higher than 28% of all known CVEs

Summary

In the Linux kernel, a race condition in iomap error handling for buffered reads can cause a NULL pointer dereference. Decrementing read_bytes_pending before error reporting allows another thread to complete the folio and detach it, leading to a crash.

Risk Assessment

An attacker could trigger this race to cause a kernel panic (denial of service) by inducing read errors and concurrent file truncation.

Recommendation

Apply the Linux kernel patch for CVE-2026-53165 immediately, which moves error reporting before the read_bytes_pending decrement.

Other vulnerabilities in Linux kernel

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Original NVD description (English source)

In the Linux kernel, the following vulnerability has been resolved: iomap: avoid potential null folio->mapping deref during error reporting When a buffered read fails, iomap_finish_folio_read() reports the error with fserror_report_io(folio->mapping->host, ...). This is called after ifs->read_bytes_pending has been decremented by the bytes attempted to be read. For a folio split across multiple read completions, the folio is only guaranteed to stay locked while read_bytes_pending > 0. Once iomap_finish_folio_read() decrements read_bytes_pending, another in-flight read can complete and end the read on the folio, which unlocks it. This allows truncate logic to run and detach the folio (set folio->mapping to NULL). The error reporting path then can dereference a NULL folio->mapping. As reported by Sam Sun, this is the race that can occur: CPU0: failed completion CPU1: final completion CPU2: truncate ----------------------- ---------------------- -------------- read_bytes_pending -= len finished = false /* preempted before fserror_report_io() */ read_bytes_pending -= len finished = true folio_end_read() truncate clears folio->mapping fserror_report_io( folio->mapping->host, ...) ^ NULL deref Fix this by reporting the error first before decrementing ifs->read_bytes_pending.

Vulnerability data from NVD (NIST) · CISA KEV · EPSS