CVE-2025-68219

cifs: fix memory leak in smb3_fs_context_parse_param error path

Published Dec 16, 2025 CVSS 3.1 · 5.5 Medium EPSS < 1% KEV · Not listed
Description
In the Linux kernel, the following vulnerability has been resolved:

cifs: fix memory leak in smb3_fs_context_parse_param error path

Add proper cleanup of ctx->source and fc->source to the
cifs_parse_mount_err error handler. This ensures that memory allocated
for the source strings is correctly freed on all error paths, matching
the cleanup already performed in the success path by
smb3_cleanup_fs_context_contents().
Pointers are also set to NULL after freeing to prevent potential
double-free issues.

This change fixes a memory leak originally detected by syzbot. The
leak occurred when processing Opt_source mount options if an error
happened after ctx->source and fc->source were successfully
allocated but before the function completed.

The specific leak sequence was:
1. ctx->source = smb3_fs_context_fullpath(ctx, '/') allocates memory
2. fc->source = kstrdup(ctx->source, GFP_KERNEL) allocates more memory
3. A subsequent error jumps to cifs_parse_mount_err
4. The old error handler freed passwords but not the source strings,
causing the memory to leak.

This issue was not addressed by commit e8c73eb7db0a ("cifs: client:
fix memory leak in smb3_fs_context_parse_param"), which only fixed
leaks from repeated fsconfig() calls but not this error path.

Patch updated with minor change suggested by kernel test robot

Remediation

No solution or workaround provided in the CVE record

Tracking

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Advisories

Source ID Title
Ubuntu USN Ubuntu USN USN-8094-1 Linux kernel vulnerabilities
Ubuntu USN Ubuntu USN USN-8095-1 Linux kernel vulnerabilities
Ubuntu USN Ubuntu USN USN-8095-2 Linux kernel (FIPS) vulnerabilities
Ubuntu USN Ubuntu USN USN-8100-1 Linux kernel (NVIDIA) vulnerabilities
Ubuntu USN Ubuntu USN USN-8094-2 Linux kernel vulnerabilities
Ubuntu USN Ubuntu USN USN-8095-3 Linux kernel (Real-time) vulnerabilities
Ubuntu USN Ubuntu USN USN-8095-4 Linux kernel (AWS) vulnerabilities
Ubuntu USN Ubuntu USN USN-8094-3 Linux kernel (Real-time) vulnerabilities
Ubuntu USN Ubuntu USN USN-8094-4 Linux kernel (Azure) vulnerabilities
Ubuntu USN Ubuntu USN USN-8125-1 Linux kernel (Azure) vulnerabilities
Ubuntu USN Ubuntu USN USN-8126-1 Linux kernel (Azure) vulnerabilities
Ubuntu USN Ubuntu USN USN-8094-5 Linux kernel (Raspberry Pi) vulnerabilities
Ubuntu USN Ubuntu USN USN-8095-5 Linux kernel (Raspberry Pi) vulnerabilities
Ubuntu USN Ubuntu USN USN-8152-1 Linux kernel (OEM) vulnerabilities
Ubuntu USN Ubuntu USN USN-8165-1 Linux kernel (Azure FIPS) vulnerabilities
Ubuntu USN Ubuntu USN USN-8261-1 Linux kernel (Xilinx) vulnerabilities
History
Type Values Removed Values Added
References
Metrics threat_severity

None

cvssV3_1

{'score': 5.5, 'vector': 'CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H'}

threat_severity

Low

Type Values Removed Values Added
Description In the Linux kernel, the following vulnerability has been resolved: cifs: fix memory leak in smb3_fs_context_parse_param error path Add proper cleanup of ctx->source and fc->source to the cifs_parse_mount_err error handler. This ensures that memory allocated for the source strings is correctly freed on all error paths, matching the cleanup already performed in the success path by smb3_cleanup_fs_context_contents(). Pointers are also set to NULL after freeing to prevent potential double-free issues. This change fixes a memory leak originally detected by syzbot. The leak occurred when processing Opt_source mount options if an error happened after ctx->source and fc->source were successfully allocated but before the function completed. The specific leak sequence was: 1. ctx->source = smb3_fs_context_fullpath(ctx, '/') allocates memory 2. fc->source = kstrdup(ctx->source, GFP_KERNEL) allocates more memory 3. A subsequent error jumps to cifs_parse_mount_err 4. The old error handler freed passwords but not the source strings, causing the memory to leak. This issue was not addressed by commit e8c73eb7db0a ("cifs: client: fix memory leak in smb3_fs_context_parse_param"), which only fixed leaks from repeated fsconfig() calls but not this error path. Patch updated with minor change suggested by kernel test robot
Title cifs: fix memory leak in smb3_fs_context_parse_param error path
First Time appeared Linux
Linux linux Kernel
CPEs cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
Vendors & Products Linux
Linux linux Kernel
References
Weaknesses

No weakness.

Sources

Status
PUBLISHED
Assigner
Linux
Published
Updated
Oct 30, 2026, 12:23 PM
Reserved
Dec 16, 2025, 1:41 PM
Status
Deferred
Published
Dec 16, 2025, 2:15 PM
Modified
Oct 30, 2026, 1:18 PM
Severity
Low
Public date
Dec 16, 2025, 12:00 AM