In the Linux kernel, the following vulnerability has been resolved: smb/server: fix possible refcount leak in smb2_sess_setup() Reference count of… (CVE-2025-40285)
A high-severity vulnerability in the Linux kernel's SMB server component (smb2_sess_setup) caused a reference count leak of ksmbd_session when a session needed to reconnect. This issue was fixed by adding the missing ksmbd_user_session_put() call to properly release the reference count.
AI Analysis
Technical Summary
The vulnerability in the Linux kernel affects the SMB server implementation, specifically in the smb2_sess_setup() function. A reference count leak occurs for the ksmbd_session object when a session requires reconnection, potentially leading to resource exhaustion or denial of service. The fix involves adding the missing ksmbd_user_session_put() to correctly decrement the reference count and prevent the leak.
Potential Impact
The vulnerability does not impact confidentiality or integrity but has a high impact on availability due to the potential for resource exhaustion caused by the reference count leak. This could lead to denial of service conditions on affected systems running the vulnerable Linux kernel SMB server.
Mitigation Recommendations
A fix for this vulnerability has been implemented in the Linux kernel by adding the missing ksmbd_user_session_put() call. Users should apply the official Linux kernel updates that include this fix. Patch status is not explicitly confirmed in the provided data; therefore, check the vendor advisory for current remediation guidance.
In the Linux kernel, the following vulnerability has been resolved: smb/server: fix possible refcount leak in smb2_sess_setup() Reference count of… (CVE-2025-40285)
Description
A high-severity vulnerability in the Linux kernel's SMB server component (smb2_sess_setup) caused a reference count leak of ksmbd_session when a session needed to reconnect. This issue was fixed by adding the missing ksmbd_user_session_put() call to properly release the reference count.
CVSS v3.1
Score 7.5high
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
The vulnerability in the Linux kernel affects the SMB server implementation, specifically in the smb2_sess_setup() function. A reference count leak occurs for the ksmbd_session object when a session requires reconnection, potentially leading to resource exhaustion or denial of service. The fix involves adding the missing ksmbd_user_session_put() to correctly decrement the reference count and prevent the leak.
Potential Impact
The vulnerability does not impact confidentiality or integrity but has a high impact on availability due to the potential for resource exhaustion caused by the reference count leak. This could lead to denial of service conditions on affected systems running the vulnerable Linux kernel SMB server.
Mitigation Recommendations
A fix for this vulnerability has been implemented in the Linux kernel by adding the missing ksmbd_user_session_put() call. Users should apply the official Linux kernel updates that include this fix. Patch status is not explicitly confirmed in the provided data; therefore, check the vendor advisory for current remediation guidance.
Technical Details
- Gcve Source
- db.gcve.eu
- Osv Id
- GHSA-7645-fj87-x9w4
- Osv Schema Version
- 1.4.0
- Aliases
- ["CVE-2025-40285"]
- Database Specific Severity
- HIGH
- Cvss Version
- 3.1
Threat ID: 6a6b72d49c2644c7f8479548
Added to database: 07/30/2026, 15:50:44 UTC
Last enriched: 07/30/2026, 17:39:11 UTC
Last updated: 09/10/2026, 19:38:45 UTC
Views: 10
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