{"id":"CVE-2026-46139","title":"smb: client: use kzalloc to zero-initialize security descriptor buffer","summary":"In the Linux kernel, the following vulnerability has been resolved:\n\nsmb: client: use kzalloc to zero-initialize security descriptor buffer\n\nCommit 62e7dd0a39c2d (\"smb: common: change the data type of num_aces\nto le16\") split struct smb_…","severity":"none","vendor":"Linux","product":"Linux","affected":["Linux >= 1593ddb37bd124c131fe635397df68e854a03108 < 4c3ed344a970aad51388ac3b0145b98318f0e21f","Linux >= da087905e3270e2291c0afae39a28e7d183e5ec3 < 941a1e6eb35440336913afc88a82103291956d5d","Linux >= 62e7dd0a39c2d0d7ff03274c36df971f1b3d2d0d < be1ef9512a3f5a755895c24f31b334342f4aa15b","Linux >= 62e7dd0a39c2d0d7ff03274c36df971f1b3d2d0d < 9bdb2ca31368b7671949dfb94a5d57ffccd01edd","Linux >= 62e7dd0a39c2d0d7ff03274c36df971f1b3d2d0d < 5e489c6c47a2ac15edbaca153b9348e42c1eacab","Linux 191f2f444745087c3c51fd6042a0e25f42315ab0","Linux >= 6.12.23 < 6.12.88","Linux >= 6.13.11 < 6.14","Linux 6.14"],"ssvc":{"exploitation":"none","automatable":"no","technicalImpact":"partial","timestamp":"2026-11-06T16:09:37.647152Z"},"published":"2026-05-28","updated":"2026-11-06","sourceUpdated":"2026-11-06T16:13:40.706Z","source":"CVEORG","sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-46139","references":[{"url":"https://git.kernel.org/stable/c/4c3ed344a970aad51388ac3b0145b98318f0e21f"},{"url":"https://git.kernel.org/stable/c/941a1e6eb35440336913afc88a82103291956d5d"},{"url":"https://git.kernel.org/stable/c/be1ef9512a3f5a755895c24f31b334342f4aa15b"},{"url":"https://git.kernel.org/stable/c/9bdb2ca31368b7671949dfb94a5d57ffccd01edd"},{"url":"https://git.kernel.org/stable/c/5e489c6c47a2ac15edbaca153b9348e42c1eacab"}],"tags":["cve.org"],"epss":0.00122,"epssPercentile":0.01984,"ingestedAt":"2026-11-06T16:57:43.332Z","slug":"CVE-2026-46139","body":"## Overview\n\nIn the Linux kernel, the following vulnerability has been resolved:\n\nsmb: client: use kzalloc to zero-initialize security descriptor buffer\n\nCommit 62e7dd0a39c2d (\"smb: common: change the data type of num_aces\nto le16\") split struct smb_acl's __le32 num_aces field into __le16\nnum_aces and __le16 reserved. The reserved field corresponds to Sbz2\nin the MS-DTYP ACL wire format, which must be zero [1].\n\nWhen building an ACL descriptor in build_sec_desc(), we are using a\nkmalloc()'ed descriptor buffer and writing the fields explicitly using\nle16() writes now. This never writes to the 2 byte reserved field,\nleaving it as uninitialized heap data.\n\nWhen the reserved field happens to contain non-zero slab garbage,\nSamba rejects the security descriptor with \"ndr_pull_security_descriptor\nfailed: Range Error\", causing chmod to fail with EINVAL.\n\nChange kmalloc() to kzalloc() to ensure the entire buffer is\nzero-initialized.\n\n\n[1] https://learn.microsoft.com/en-us/openspecs/windows_protocols/ms-dtyp/20233ed8-a6c6-4097-aafa-dd545ed24428\n\n## Affected\n\n- `Linux >= 1593ddb37bd124c131fe635397df68e854a03108 < 4c3ed344a970aad51388ac3b0145b98318f0e21f`\n- `Linux >= da087905e3270e2291c0afae39a28e7d183e5ec3 < 941a1e6eb35440336913afc88a82103291956d5d`\n- `Linux >= 62e7dd0a39c2d0d7ff03274c36df971f1b3d2d0d < be1ef9512a3f5a755895c24f31b334342f4aa15b`\n- `Linux >= 62e7dd0a39c2d0d7ff03274c36df971f1b3d2d0d < 9bdb2ca31368b7671949dfb94a5d57ffccd01edd`\n- `Linux >= 62e7dd0a39c2d0d7ff03274c36df971f1b3d2d0d < 5e489c6c47a2ac15edbaca153b9348e42c1eacab`\n- `Linux 191f2f444745087c3c51fd6042a0e25f42315ab0`\n- `Linux >= 6.12.23 < 6.12.88`\n- `Linux >= 6.13.11 < 6.14`\n- `Linux 6.14`\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.","depth":"sunlit","depthScore":3,"depthScoreParts":{"impact":2.8,"likelihood":0,"exploitation":0,"ransomware":0},"changes":[]}