CVE-2026-98223
mm: filemap: retain mapped dropbehind folios
Description
In the Linux kernel, the following vulnerability has been resolved: mm: filemap: retain mapped dropbehind folios Fault-around can map ready dropbehind folios without going through the normal page-cache lookup that clears dropbehind. A mapping represents a competing cached user, so retain the folio instead of forcibly unmapping it when writeback completes. For a mapped folio, folio_unmap_invalidate() can call unmap_mapping_folio(), which takes i_mmap_rwsem and may sleep. Retaining mapped folios avoids this path when folio_end_dropbehind() runs in non-preemptible task context. Tal was able to trigger a sleeping-in-atomic warning due to this [1]. Unmapped dropbehind folios continue through the existing invalidation path.
INFO
Published Date :
Oct. 6, 2026, 9:18 a.m.
Last Modified :
Oct. 19, 2026, 10:18 a.m.
Remotely Exploit :
No
Source :
416baaa9-dc9f-4396-8d5f-8c081fb06d67
Solution
- Update the Linux kernel to include the fix for retained mapped folios.
- Avoid unmapping folios when writeback completes.
- Ensure non-preemptible task context for folio_end_dropbehind().
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-98223.
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-98223 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-98223
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
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The following list is the news that have been mention
CVE-2026-98223 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-98223 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
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CVE Modified by 416baaa9-dc9f-4396-8d5f-8c081fb06d67
Oct. 19, 2026
Action Type Old Value New Value Added Affected Affected value modified. <a href="https://github.com/CVEProject/cvelistV5/blob/main/cves/2026/98xxx/CVE-2026-98223.json">CVE-2026-98223</a> -
New CVE Received by 416baaa9-dc9f-4396-8d5f-8c081fb06d67
Oct. 06, 2026
Action Type Old Value New Value Added Description In the Linux kernel, the following vulnerability has been resolved: mm: filemap: retain mapped dropbehind folios Fault-around can map ready dropbehind folios without going through the normal page-cache lookup that clears dropbehind. A mapping represents a competing cached user, so retain the folio instead of forcibly unmapping it when writeback completes. For a mapped folio, folio_unmap_invalidate() can call unmap_mapping_folio(), which takes i_mmap_rwsem and may sleep. Retaining mapped folios avoids this path when folio_end_dropbehind() runs in non-preemptible task context. Tal was able to trigger a sleeping-in-atomic warning due to this [1]. Unmapped dropbehind folios continue through the existing invalidation path. Added Affected New affected value received. <a href="https://github.com/CVEProject/cvelistV5/blob/main/cves/2026/98xxx/CVE-2026-98223.json">CVE-2026-98223</a> Added Reference https://git.kernel.org/stable/c/2897601dffe576fcd87a4259102f41f7fb0cbfc8 Added Reference https://git.kernel.org/stable/c/77c0fade37c80e8aa16ac048a9828249055e3f66 Added Reference https://git.kernel.org/stable/c/848d2ce2fce15fbdc083fbf9691bfa72911033c4