Bug 2555215 (CVE-2026-98843) - CVE-2026-98843 kernel: netfs: zero gaps in read-gaps folio to avoid writing back stale data
Summary: CVE-2026-98843 kernel: netfs: zero gaps in read-gaps folio to avoid writing b...
Keywords:
Status: NEW
Alias: CVE-2026-98843
Product: Security Response
Classification: Other
Component: vulnerability
Version: unspecified
Hardware: All
OS: Linux
medium
medium
Target Milestone: ---
Assignee: Product Security DevOps Team
QA Contact:
URL:
Whiteboard:
Depends On:
Blocks:
TreeView+ depends on / blocked
 
Reported: 2026-10-18 16:02 UTC by OSIDB Bzimport
Modified: 2026-10-23 21:51 UTC (History)
17 users (show)

Fixed In Version:
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Description OSIDB Bzimport 2026-10-18 16:02:25 UTC
In the Linux kernel, the following vulnerability has been resolved:

netfs: zero gaps in read-gaps folio to avoid writing back stale data

netfs_read_gaps() leaves gaps around a streaming write's dirty region
unread on the server side, so a short/EOF response there left stale
folio content that later got written back.

Zero it after the read completes, not before: netfs_wait_for_read()
returns rreq->transferred once ret >= 0, so build an iterator over the
same bvec array the read used, advance past ret, and zero the rest.
The dirty region already maps to sink pages in that array rather than
the real folio, so this can't touch it, and only the actual shortfall
gets zeroed instead of the whole gap upfront.


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