# CVE-2026-53165: linux: In the Linux kernel, the following vulnerability has been resolved:  iomap: avoid potential null folio->mapping deref...

CVE-2026-53165 is fixed in linux on 1 platform by DEBIAN-CVE-2026-53165 (version 7.0.13-1), released June 28, 2026. It is not reported as exploited. Patch Radar priority: High.

- Web page: https://patchblox.com/security/cve/CVE-2026-53165
- Priority: High
- CVSS: 7.5 (high)
- EPSS: 0.0049
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Jun 25, 2026

## Description

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.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | linux Debian 14 | 7.0.13-1 | [DEBIAN-CVE-2026-53165](https://patchblox.com/security/data/fix/linux/debian-cve-2026-53165.md) | Jun 28, 2026 |

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