In the Linux kernel, the following vulnerability has been resolved: ksmbd: fix durable reconnect error path file lifetime After a durable reconnect… (CVE-2026-64016)
In the Linux kernel, the following vulnerability has been resolved: ksmbd: fix durable reconnect error path file lifetime After a durable reconnect succeeds, ksmbd_reopen_durable_fd() republishes the same ksmbd_file into the session volatile-id table. If smb2_open() then takes a later error path, cleanup first calls ksmbd_fd_put(work, fp) and then unconditionally calls ksmbd_put_durable_fd(dh_info.fp). In this case fp and dh_info.fp are the same object. The first put drops the reconnect lookup reference, but the final durable put can run __ksmbd_close_fd(NULL, fp). Because the final close is not session-aware, it can free the file object without removing the volatile-id entry that was just published into the session table. Use the session-aware put for the final reconnect drop when the reconnect had already succeeded and the error path is cleaning up the republished file. Earlier reconnect failures, before fp is assigned to dh_info.fp, keep using the durable-only put path.
AI Analysis
Technical Summary
The vulnerability in the Linux kernel's ksmbd module concerns the handling of durable reconnects. After a successful durable reconnect, the same ksmbd_file is republished into the session volatile-id table. If smb2_open() subsequently follows an error path, it first calls ksmbd_fd_put() and then unconditionally calls ksmbd_put_durable_fd() on the same file object. The first call drops the reconnect lookup reference, but the second call can invoke __ksmbd_close_fd() without session awareness, freeing the file object without removing the volatile-id entry. This improper cleanup can leave stale entries in the session table. The fix changes the final cleanup to use a session-aware put method when the reconnect has succeeded, preventing premature freeing and maintaining session consistency.
Potential Impact
The vulnerability can cause improper cleanup of file objects in the ksmbd session table after durable reconnects, potentially leading to stale volatile-id entries and inconsistent kernel state. While no direct exploitation or known attacks are reported, this could affect kernel stability or reliability of SMB server sessions.
Mitigation Recommendations
Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. Since this is a kernel vulnerability, applying the official Linux kernel updates that address CVE-2026-64016 is recommended once available. No specific workaround is described in the provided data.
In the Linux kernel, the following vulnerability has been resolved: ksmbd: fix durable reconnect error path file lifetime After a durable reconnect… (CVE-2026-64016)
Description
In the Linux kernel, the following vulnerability has been resolved: ksmbd: fix durable reconnect error path file lifetime After a durable reconnect succeeds, ksmbd_reopen_durable_fd() republishes the same ksmbd_file into the session volatile-id table. If smb2_open() then takes a later error path, cleanup first calls ksmbd_fd_put(work, fp) and then unconditionally calls ksmbd_put_durable_fd(dh_info.fp). In this case fp and dh_info.fp are the same object. The first put drops the reconnect lookup reference, but the final durable put can run __ksmbd_close_fd(NULL, fp). Because the final close is not session-aware, it can free the file object without removing the volatile-id entry that was just published into the session table. Use the session-aware put for the final reconnect drop when the reconnect had already succeeded and the error path is cleaning up the republished file. Earlier reconnect failures, before fp is assigned to dh_info.fp, keep using the durable-only put path.
CVSS v3.1
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
The vulnerability in the Linux kernel's ksmbd module concerns the handling of durable reconnects. After a successful durable reconnect, the same ksmbd_file is republished into the session volatile-id table. If smb2_open() subsequently follows an error path, it first calls ksmbd_fd_put() and then unconditionally calls ksmbd_put_durable_fd() on the same file object. The first call drops the reconnect lookup reference, but the second call can invoke __ksmbd_close_fd() without session awareness, freeing the file object without removing the volatile-id entry. This improper cleanup can leave stale entries in the session table. The fix changes the final cleanup to use a session-aware put method when the reconnect has succeeded, preventing premature freeing and maintaining session consistency.
Potential Impact
The vulnerability can cause improper cleanup of file objects in the ksmbd session table after durable reconnects, potentially leading to stale volatile-id entries and inconsistent kernel state. While no direct exploitation or known attacks are reported, this could affect kernel stability or reliability of SMB server sessions.
Mitigation Recommendations
Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. Since this is a kernel vulnerability, applying the official Linux kernel updates that address CVE-2026-64016 is recommended once available. No specific workaround is described in the provided data.
Technical Details
- Gcve Source
- db.gcve.eu
- Osv Id
- GHSA-w63r-7cfm-vm57
- Osv Schema Version
- 1.4.0
- Aliases
- ["CVE-2026-64016"]
- Ecosystems
- []
- Database Specific Severity
- null
- Cvss Version
- null
Threat ID: 6a5d27a92a4a8d598912d23b
Added to database: 07/19/2026, 19:38:17 UTC
Last enriched: 07/19/2026, 19:58:05 UTC
Last updated: 07/20/2026, 19:49:24 UTC
Views: 14
Community Reviews
0 reviewsCrowdsource mitigation strategies, share intel context, and vote on the most helpful responses. Sign in to add your voice and help keep defenders ahead.
Want to contribute mitigation steps or threat intel context? Sign in or create an account to join the community discussion.
Actions
Updates to AI analysis require Pro Console access. Upgrade inside Console → Billing.
Need more coverage?
Upgrade to Pro Console for AI refresh and higher limits.
For incident response and remediation, OffSeq services can help resolve threats faster.
Latest Threats
Check if your credentials are on the dark web
Instant breach scanning across billions of leaked records. Free tier available.