Paper/Archive/CVE-2026-46195

CVE-2026-46195

Linux Linux — smb: client: validate dacloffset before building DACL pointers

Description · from the CVE record

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.

Affected

ProductAffectedFixed inSource
Linuxbc3e9dd9d104ca1b75644eab87b38ce8a924aef4 – < 5de2665e913a10ad70aaeecf736b97276e83d9955de2665e913a10ad70aaeecf736b97276e83d995CNA
Linuxbc3e9dd9d104ca1b75644eab87b38ce8a924aef4 – < f9dc3be8f403c1216df73e57221f44b045e7ee0bf9dc3be8f403c1216df73e57221f44b045e7ee0bCNA
Linuxbc3e9dd9d104ca1b75644eab87b38ce8a924aef4 – < ba7f71b6161c0943dafc367565e5843d16b7d505ba7f71b6161c0943dafc367565e5843d16b7d505CNA
Linuxbc3e9dd9d104ca1b75644eab87b38ce8a924aef4 – < 3b1ddba19e77ee35241cd27f16dc3e8d14e08db73b1ddba19e77ee35241cd27f16dc3e8d14e08db7CNA
Linuxbc3e9dd9d104ca1b75644eab87b38ce8a924aef4 – < c688f3ed73d31943334ad2139cb02ec49664322ac688f3ed73d31943334ad2139cb02ec49664322aCNA
Linuxbc3e9dd9d104ca1b75644eab87b38ce8a924aef4 – < 8bd07e417b6bda67e317920584e48cb6ee442a8a8bd07e417b6bda67e317920584e48cb6ee442a8aCNA
Linuxbc3e9dd9d104ca1b75644eab87b38ce8a924aef4 – < f98b48151cc502ada59d9778f0112d21f2586ca3f98b48151cc502ada59d9778f0112d21f2586ca3CNA
Linux5.125.15.210CNA
Red Hat Enterprise Linux 8see advisory0:4.18.0-553.126.1.rt7.467.el8_10redhat-SADP
Red Hat Enterprise Linux 8see advisory0:4.18.0-553.126.1.el8_10redhat-SADP
Red Hat Enterprise Linux 9see advisory0:5.14.0-687.12.1.el9_8redhat-SADP
Red Hat Enterprise Linux 10see advisory–redhat-SADP

Scores by source

Linux (CNA)9.8CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
redhat-SADP (CNA)7.5CVSS:3.1/AV:A/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
CISA ADPSSVCExploitation: none · Automatable: yes · Technical impact: total

References

refgit.kernel.org/stable/c/5de2665e913a10ad70aaeecf736b97276e83d995refgit.kernel.org/stable/c/f9dc3be8f403c1216df73e57221f44b045e7ee0brefgit.kernel.org/stable/c/ba7f71b6161c0943dafc367565e5843d16b7d505refgit.kernel.org/stable/c/3b1ddba19e77ee35241cd27f16dc3e8d14e08db7refgit.kernel.org/stable/c/c688f3ed73d31943334ad2139cb02ec49664322arefgit.kernel.org/stable/c/8bd07e417b6bda67e317920584e48cb6ee442a8arefgit.kernel.org/stable/c/f98b48151cc502ada59d9778f0112d21f2586ca3refaccess.redhat.com/security/cve/CVE-2026-46195refbugzilla.redhat.com/show_bug.cgi?id=2482606refsecurity.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-46195.jsonadvisoryaccess.redhat.com/errata/RHSA-2026:21556advisoryaccess.redhat.com/errata/RHSA-2026:21706advisoryaccess.redhat.com/errata/RHSA-2026:21745refcert-portal.siemens.com/productcert/html/ssa-784472.html