CVE-2026-46195smb: client: validate dacloffset before building DACL pointers
Updated under an hour ago ()
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It affects Linux and 3 other products. Add what you run to find out whether that includes you.
No exploitation reported and no EPSS estimate yet.
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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.
- CVSS
- 9.8 CRITICAL (v3.1, CNA)CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
- Weakness (CWE)
- CWE-787
- Known exploited
- Not in CISA's KEV catalog
- EPSS (exploitation in the next 30 days)
- Not loaded for this CVE
- Assigned by
- Linux
- NVD analysis
- Modified
- Record last updated
- Oct 16, 2026
- First seen by InfoSec Signals
- Oct 9, 2026
Affected products
Linux Linux linux:linux (from the name) | from bc3e9dd9d104ca1b75644eab87b38ce8a924aef4 before 5de2665e913a10ad70aaeecf736b97276e83d995; from bc3e9dd9d104ca1b75644eab87b38ce8a924aef4 before f9dc3be8f403c1216df73e57221f44b045e7ee0b; from bc3e9dd9d104ca1b75644eab87b38ce8a924aef4 before ba7f71b6161c0943dafc367565e5843d16b7d505; from bc3e9dd9d104ca1b75644eab87b38ce8a924aef4 before 3b1ddba19e77ee35241cd27f16dc3e8d14e08db7; from bc3e9dd9d104ca1b75644eab87b38ce8a924aef4 before c688f3ed73d31943334ad2139cb02ec49664322a; from bc3e9dd9d104ca1b75644eab87b38ce8a924aef4 before 8bd07e417b6bda67e317920584e48cb6ee442a8a; from bc3e9dd9d104ca1b75644eab87b38ce8a924aef4 before f98b48151cc502ada59d9778f0112d21f2586ca3 | CNA record |
Red Hat Red Hat Enterprise Linux 8 redhat:enterprise_linux | from 0:4.18.0-553.126.1.rt7.467.el8_10 not affected | CISA ADP |
Siemens SIMATIC S7-1500 TM MFP - GNU/Linux subsystem siemens:simatic_s7_1500_tm_mfp_gnu_linux_subsystem (from the name) | all versions | CISA ADP |
linux linux_kernel linux:linux_kernel | from 5.12 before 6.6.140; from 6.7 before 6.12.88; from 6.13 before 6.18.30; from 6.19 before 7.0.7; 7.1; 7.1 | NVD |
References
- https://git.kernel.org/stable/c/5de2665e913a10ad70aaeecf736b97276e83d995
- https://git.kernel.org/stable/c/f9dc3be8f403c1216df73e57221f44b045e7ee0b
- https://git.kernel.org/stable/c/ba7f71b6161c0943dafc367565e5843d16b7d505patch
- https://git.kernel.org/stable/c/3b1ddba19e77ee35241cd27f16dc3e8d14e08db7patch
- https://git.kernel.org/stable/c/c688f3ed73d31943334ad2139cb02ec49664322apatch
- https://git.kernel.org/stable/c/8bd07e417b6bda67e317920584e48cb6ee442a8apatch
- https://git.kernel.org/stable/c/f98b48151cc502ada59d9778f0112d21f2586ca3patch
- https://access.redhat.com/errata/RHSA-2026:21556
- https://access.redhat.com/errata/RHSA-2026:21706
- https://access.redhat.com/errata/RHSA-2026:21745
- https://access.redhat.com/security/cve/CVE-2026-46195
- https://bugzilla.redhat.com/show_bug.cgi?id=2482606
- https://cert-portal.siemens.com/productcert/html/ssa-784472.html
- https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-46195.json
The CVE record on cve.org NVD's entry
The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.