What’s Vulnerable › Vulnerabilities

CVE-2026-98686: smb: client: discard post-EOF pagecache when extending a file via zero range

• Severity: unknown
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.2% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-10-18 · updated 2026-10-30

Description

In the Linux kernel, the following vulnerability has been resolved: smb: client: discard post-EOF pagecache when extending a file via zero range smb3_zero_range() removed the pagecache only for the range being zeroed, so when it extends the file the folio straddling the old EOF - which may hold data dirtied past EOF through an mmap - was never dropped and became visible as file content once the file was extended. Lower the discard boundary to the smaller of the zero-range offset and the old EOF.

Affected products

• Linux: 5.1 — fixed in 7.3

How to fix

Upgrade to a fixed version: Linux 7.3. Check the vendor advisory for mitigations.

References

• https://git.kernel.org/stable/c/03408d15c5405f8dc3e1a114cdce2174027a85f6
• https://git.kernel.org/stable/c/1ecf89d8efca618e0c758c06b9a1fdde8bd941da
• https://git.kernel.org/stable/c/3df27277f8f95345d4a6c57367824bf1aefdbf66
• https://git.kernel.org/stable/c/6a8279c98ad289b27c0bdb11adb3f0c0b7fd456d
• https://git.kernel.org/stable/c/94949b6b2f2bf0dba2e8786aed0b08cc6bc3a183
• https://git.kernel.org/stable/c/b75dadb50a25eed525264bf6fea44fad94e7626f
• https://git.kernel.org/stable/c/da4fe97fb6c730d9c94a115c7bfa6f98e0d578d0

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