---
cve: "CVE-2026-53165"
severity: "HIGH"
cvss: 7.5
epss: "34%"
vendor: "Linux"
kev: false
exploited: false
published: "2026-06-25 09:16:33"
tags: [cve, security, high]
source: tsecurity.de CVE-Dossier
exported: "2026-09-07T12:18:15+02:00"
---

# CVE-2026-53165

> 7.5 HIGH

## Beschreibung

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.

## CVSS-Vektor

```
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
```

| Metrik | Wert | Bewertung |
|---|---|---|
| AV Angriffsvektor | Netzwerk | bad |
| AC Komplexität | Gering | bad |
| PR Privilegien | Keine | bad |
| UI Interaktion | Keine | bad |
| S Scope | Unverändert | good |
| C Vertraulichkeit | Keine | good |
| I Integrität | Keine | good |
| A Verfügbarkeit | Hoch | bad |

## Patch verfügbar (OSV)

- Kernel ≥ 7.0.13

## Referenzen

- <https://git.kernel.org/stable/c/1ad453817a4077230d1ba88eb0868f05f824449a>
- <https://git.kernel.org/stable/c/2eea7f44b9c8b42fd7d3a1a87c06a7cd1b99c327>

---
_Exportiert aus dem [tsecurity.de CVE-Dossier](https://tsecurity.de/cve?cve=CVE-2026-53165) · Datenquellen: EUVD (ENISA), NVD, OSV, CISA KEV, FIRST EPSS, Exploit-DB, BSI BITS_