CVE-2025-68219

/// Technical 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 free

/// Remediation

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

/// References