In the Linux kernel, the following vulnerability has been resolved:
cifs: clear tcon after cifsFileInfo_put() in cifs_file_set_size()
When the else branch of cifs_file_set_size() finds a writable file handle
via find_writable_file(), it borrows tcon and server from the handle's
tlink, attempts the handle-based set_file_size() RPC, and then releases
the handle with cifsFileInfo_put().
If set_file_size() fails, execution falls through to the path-based
fallback, which reuses the borrowed tcon and server under the
"if (tcon == NULL)" guard. Since tcon is not NULL at that point, the
guard is skipped. If cifsFileInfo_put() dropped the last reference on a
tlink that was already removed from the tlink tree (TCON_LINK_IN_TREE
cleared, as happens during reconnection or session teardown),
cifs_put_tlink() will have freed tcon; the subsequent set_path_size()
call is then a use-after-free.
Setting tcon = NULL after cifsFileInfo_put() causes the existing guard
to take the cifs_sb_tlink() path, which acquires a fresh reference for
the path-based operation or fails cleanly if the session is gone.
cifs: clear tcon after cifsFileInfo_put() in cifs_file_set_size()
When the else branch of cifs_file_set_size() finds a writable file handle
via find_writable_file(), it borrows tcon and server from the handle's
tlink, attempts the handle-based set_file_size() RPC, and then releases
the handle with cifsFileInfo_put().
If set_file_size() fails, execution falls through to the path-based
fallback, which reuses the borrowed tcon and server under the
"if (tcon == NULL)" guard. Since tcon is not NULL at that point, the
guard is skipped. If cifsFileInfo_put() dropped the last reference on a
tlink that was already removed from the tlink tree (TCON_LINK_IN_TREE
cleared, as happens during reconnection or session teardown),
cifs_put_tlink() will have freed tcon; the subsequent set_path_size()
call is then a use-after-free.
Setting tcon = NULL after cifsFileInfo_put() causes the existing guard
to take the cifs_sb_tlink() path, which acquires a fresh reference for
the path-based operation or fails cleanly if the session is gone.
Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).
| Vendor | Product | Default status | Versions | ||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Linux | Linux | unaffected |
|
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| Linux | Linux | affected |
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Advisories
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Fixes
Solution
No solution given by the vendor.
Workaround
No workaround given by the vendor.
References
History
Fri, 11 Sep 2026 23:45:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Description | In the Linux kernel, the following vulnerability has been resolved: cifs: clear tcon after cifsFileInfo_put() in cifs_file_set_size() When the else branch of cifs_file_set_size() finds a writable file handle via find_writable_file(), it borrows tcon and server from the handle's tlink, attempts the handle-based set_file_size() RPC, and then releases the handle with cifsFileInfo_put(). If set_file_size() fails, execution falls through to the path-based fallback, which reuses the borrowed tcon and server under the "if (tcon == NULL)" guard. Since tcon is not NULL at that point, the guard is skipped. If cifsFileInfo_put() dropped the last reference on a tlink that was already removed from the tlink tree (TCON_LINK_IN_TREE cleared, as happens during reconnection or session teardown), cifs_put_tlink() will have freed tcon; the subsequent set_path_size() call is then a use-after-free. Setting tcon = NULL after cifsFileInfo_put() causes the existing guard to take the cifs_sb_tlink() path, which acquires a fresh reference for the path-based operation or fails cleanly if the session is gone. | |
| Title | cifs: clear tcon after cifsFileInfo_put() in cifs_file_set_size() | |
| First Time appeared |
Linux
Linux linux Kernel |
|
| CPEs | cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* | |
| Vendors & Products |
Linux
Linux linux Kernel |
|
| References |
|
Projects
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MITRE
Status: PUBLISHED
Assigner: Linux
Published:
Updated: 2026-09-11T19:45:34.036Z
Reserved: 2026-09-11T19:38:34.740Z
Link: CVE-2026-89641
Vulnrichment
No data.
NVD
Status : Received
Published: 2026-09-11T20:19:49.867
Modified: 2026-09-11T20:19:49.867
Link: CVE-2026-89641
Redhat
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OpenCVE Enrichment
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Weaknesses
No weakness.