Answer in brief
CVE-2026-89641 records a High severity (CVSS 7.8) vulnerability in cifs: clear tcon after cifsFileInfo_put() in cifs_file_set_size(). The current sources do not mark it as known exploited. The current feed maps Linux/Linux (generic), Linux/Linux (generic). Check affected ranges and fixed versions before updating.
Analysis pending evidence review
HOL Guard separates source facts from reviewed analysis. See the methodology.
CVSS is 7.8. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.
Analysis status
Analysis pending evidence review
Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.
The current feed maps Linux/Linux (generic), Linux/Linux (generic). Check affected ranges and fixed versions before updating.
| Package | Affected range | Fixed version |
|---|---|---|
| Linux/Linuxgeneric | >=110fee6b9bb58a5c50047fc2594d415f741b591e <4f18c9e7ee464aaae5cd9fccdb943b3fcb4655d4 || >=110fee6b9bb58a5c50047fc2594d415f741b591e <4bea15d9c7683218f57b8c1f5f0aa75cab76af8d || >=110fee6b9bb58a5c50047fc2594d415f741b591e <b96db32fed8dfb2478d7c208f89bf383beed1535 | 4f18c9e7ee464aaae5cd9fccdb943b3fcb4655d4, 4bea15d9c7683218f57b8c1f5f0aa75cab76af8d, b96db32fed8dfb2478d7c208f89bf383beed1535 |
| Linux/Linuxgeneric | 6.18 | Not reported |
Published upstream
Sep 11, 2026
Evidence: source:cvelist:source_dates:source-dates:recordSource modified
Oct 19, 2026
Evidence: source:cvelist:source_dates:source-dates:recordFirst seen by HOL
Sep 11, 2026
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.
Quoted source text, attributed separately from HOL analysis.