CVE-2025-40268 Details
Description
In the Linux kernel, the following vulnerability has been resolved: cifs: client: fix memory leak in smb3_fs_context_parse_param The user calls fsconfig twice, but when the program exits, free() only frees ctx->source for the second fsconfig, not the first. Regarding fc->source, there is no code in the fs context related to its memory reclamation. To fix this memory leak, release the source memory corresponding to ctx or fc before each parsing. syzbot reported: BUG: memory leak unreferenced object 0xffff888128afa360 (size 96): backtrace (crc 79c9c7ba): kstrdup+0x3c/0x80 mm/util.c:84 smb3_fs_context_parse_param+0x229b/0x36c0 fs/smb/client/fs_context.c:1444 BUG: memory leak unreferenced object 0xffff888112c7d900 (size 96): backtrace (crc 79c9c7ba): smb3_fs_context_fullpath+0x70/0x1b0 fs/smb/client/fs_context.c:629 smb3_fs_context_parse_param+0x2266/0x36c0 fs/smb/client/fs_context.c:1438
A memory leak vulnerability has been identified in the Linux kernel's CIFS client, specifically within the SMB3 file system context parsing function. When the user calls 'fsconfig' twice, the memory allocated for the first call is not properly freed before the program exits. This issue arises because there is no existing code to reclaim the memory for 'fc->source' in the file system context. The vulnerability has been reported by syzbot, which highlighted the unreferenced objects causing the memory leak.
Users can upgrade to the latest version of the Linux kernel where this vulnerability has been addressed. The specific commit that resolves this issue is available in the Linux kernel stable tree.
Metrics
CVSS 4.0 Severity and Vector Strings:
VolerionCVSS 3.x Severity and Vector Strings:
No data available for CVSS Version 2.0 on this CVE.
Volerion
Assessed Dec 6, 2025References to Advisories, Solutions, and Tools
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| URL | Source(s) | Tag(s) |
|---|---|---|
| https://git.kernel.org/stable/c/4515743cc7a42e1d67468402a6420c195532a6fa | kernel.org | Source CodeVendor |
| https://git.kernel.org/stable/c/48c17341577e25a22feb13d694374b61d974edbc | kernel.org | Source CodeVendor |
| https://git.kernel.org/stable/c/868fc62811d3fabcf5685e14f36377a855d5412d | kernel.org | Source CodeVendor |
| https://git.kernel.org/stable/c/e8c73eb7db0a498cd4b22d2819e6ab1a6f506bd6 | kernel.org | Source CodeVendor |
Weakness Enumeration
No weakness enumeration is available for this CVE.
Affected Products
| Product | Versions |
|---|---|
| Linux kernel | All versions |
CPE
Remediation
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Change History
2 change records found show changes
| Date | Action | Recorded By |
|---|---|---|
| Jun 17, 2026 | CVE Modified | kernel.org |
| Dec 6, 2025 | New CVE Received | kernel.org |