CVE-2026-98124: Linux kernel · smb/client: invalidate fscache for fallocate range operations
Affects Linux kernelSource CVE Database V5
Not known to be exploited · fixed in dd8b1e808f5c19479e6ed47e2f88a1fd46f8b0e5 : update Linux kernel when convenient.
Data as of 26 Oct 2026, 14:18 UTC
Rated by Threat Radar · CVSS not yet scored by NVD
- EPSS
- 0.1% chance of exploitation in 30 days – higher than 8% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
- Patch
- Available – fixed in dd8b1e808f5c19479e6ed47e2f88a1fd46f8b0e5, cc7202a51b8777a757bda9dcfbf339f828c6a130, 448ba0ae65ca61064183564d2983c9aa59bd6ba7 +1
Exploitation evidence
Disclosed: evidence found.
CVE published 25 Sep 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.
What to do
Upgrade Linux kernel to dd8b1e808f5c19479e6ed47e2f88a1fd46f8b0e5, cc7202a51b8777a757bda9dcfbf339f828c6a130, 448ba0ae65ca61064183564d2983c9aa59bd6ba7 or 93c6e5a8d7c5071d586c1411596d5db5faad22b2.
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in– |
Description
In the Linux kernel, the following vulnerability has been resolved: smb/client: invalidate fscache for fallocate range operations smb3_zero_range(), smb3_punch_hole(), smb3_insert_range(), and smb3_collapse_range() modify file contents through server-side range operations. These operations discard the affected page cache, but leave the FS-Cache cookie valid, so a later read may return data cached before the range operation. Fix this by invalidating FS-Cache after outstanding I/O has completed and before modifying the file on the server. Run the following as root on a CIFS mount with fsc enabled and an active CacheFiles backend: bash -c ' MNT=/mnt/cifs FILE="$MNT/repro" # Generate four 1 MiB random blocks: [A][B][C][D]. dd if=/dev/urandom of=/tmp/src bs=1M count=4 status=none # Expected contents after zeroing B: [A][zero][C][D]. cp /tmp/src /tmp/expected dd if=/dev/zero of=/tmp/expected bs=1M seek=1 count=1 \ conv=notrunc status=none cp /tmp/src "$FILE" # Populate FS-Cache, then discard the page cache. sync echo 1 > /proc/sys/vm/drop_caches cat "$FILE" > /dev/null sync echo 1 > /proc/sys/vm/drop_caches fallocate --zero-range -o 1M -l 1M "$FILE" if cmp -s /tmp/expected "$FILE"; then echo "readback: OK" else echo "readback: STALE DATA" fi ' Before this change, the readback differs from /tmp/expected: readback: STALE DATA After this change, it matches: readback: OK
References
- git.kernel.org/stable/c/cc7202a51b8777a757bda9dcfbf339f828c6a130 (opens in a new tab)
- git.kernel.org/stable/c/dd8b1e808f5c19479e6ed47e2f88a1fd46f8b0e5 (opens in a new tab)
- git.kernel.org/stable/c/93c6e5a8d7c5071d586c1411596d5db5faad22b2 (opens in a new tab)
- git.kernel.org/stable/c/448ba0ae65ca61064183564d2983c9aa59bd6ba7 (opens in a new tab)