CVE-2026-46195

Description

In the Linux kernel, the following vulnerability has been resolved: smb: client: validate dacloffset before building DACL pointers parse_sec_desc(), build_sec_desc(), and the chown path in id_mode_to_cifs_acl() all add the server-supplied dacloffset to pntsd before proving a DACL header fits inside the returned security descriptor. On 32-bit builds a malicious server can return dacloffset near U32_MAX, wrap the derived DACL pointer below end_of_acl, and then slip past the later pointer-based bounds checks. build_sec_desc() and id_mode_to_cifs_acl() can then dereference DACL fields from the wrapped pointer in the chmod/chown rewrite paths. Validate dacloffset numerically before building any DACL pointer and reuse the same helper at the three DACL entry points.

References

• https://git.kernel.org/stable/c/3b1ddba19e77ee35241cd27f16dc3e8d14e08db7
• https://git.kernel.org/stable/c/8bd07e417b6bda67e317920584e48cb6ee442a8a
• https://git.kernel.org/stable/c/ba7f71b6161c0943dafc367565e5843d16b7d505
• https://git.kernel.org/stable/c/c688f3ed73d31943334ad2139cb02ec49664322a
• https://git.kernel.org/stable/c/f98b48151cc502ada59d9778f0112d21f2586ca3