ksmbd: prevent path traversal bypass by restricting caseless retry
In the Linux kernel, the following vulnerability has been resolved: ksmbd: prevent path traversal bypass by restricting caseless retry ksmbd_vfs_path_lookup() enforces LOOKUP_BENEATH to restrict path resolution within the share root. When a crafted path attempts to escape the share boundary using parent-directory components ('..'), vfs_path_parent_lookup() detects this and immediately fails, returning -EXDEV. However, a bug exists in __ksmbd_vfs_kern_path() under caseless mode. The function fails to intercept the -EXDEV error and erroneously falls through to the caseless retry logic, which is intended only for genuinely missing files. During this retry process, the path is reconstructed, leading to an unintended LOOKUP_BENEATH bypass that allows write-capable users to create zero-length files or directories outside the exported share. Fix this by ensuring that the execution only proceeds to the caseless lookup retry when the error is specifically -ENOENT. Any other errors, such as -EXDEV from a path traversal attempt, must be returned immediately.
CVE-2026-64400
Primary source · Revision 1
Imported from structured advisory data. Source references identify upstream records or fields; verify affected versions and your deployed configuration.
Security context
Source reference: cve:CVE-2026-64400
Linux
Source reference: /containers/cna/affected/0/product
- Affected versions
- Not stated in this record
- Fixed versions
- Not stated in this record
- Prerequisites
- Not stated in this record
Linux
Source reference: /containers/cna/affected/1/product
- Affected versions
- Not stated in this record
- Fixed versions
- Not stated in this record
- Prerequisites
- Not stated in this record
Structured affected-version data
Original package identities and version rules from this source.
[
{
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"product": "Linux",
"versions": [
{
"status": "affected",
"version": "74d7970febf7e9005375aeda0df821d2edffc9f7",
"lessThan": "eec1dd2586c4016b7555a5d047db2b3756459fb2",
"versionType": "git"
},
{
"status": "affected",
"version": "74d7970febf7e9005375aeda0df821d2edffc9f7",
"lessThan": "a1c331d98313380c38f616c8b28b890ec8ef9c28",
"versionType": "git"
},
{
"status": "affected",
"version": "74d7970febf7e9005375aeda0df821d2edffc9f7",
"lessThan": "cfb5a56c218888f9d74165dff0c282cd0be97983",
"versionType": "git"
},
{
"status": "affected",
"version": "74d7970febf7e9005375aeda0df821d2edffc9f7",
"lessThan": "8c9a4f1327eb71efbf14842e7b8a6d965077eb67",
"versionType": "git"
},
{
"status": "affected",
"version": "74d7970febf7e9005375aeda0df821d2edffc9f7",
"lessThan": "54bab9ba5a9f156ffa9324fcbe5a356fd0242f95",
"versionType": "git"
},
{
"status": "affected",
"version": "019aae488dbc67c97a33db03652e20e2c9e3afa7",
"versionType": "git"
},
{
"status": "affected",
"version": "6927ffe7479c72e7ebf885507227266a75f7c97d",
"versionType": "git"
},
{
"status": "affected",
"version": "ef6cc1c465786b3e4e735d1ab8b616b3e94402df",
"versionType": "git"
},
{
"status": "affected",
"version": "5.15.145",
"lessThan": "5.16",
"versionType": "semver"
},
{
"status": "affected",
"version": "6.1.71",
"lessThan": "6.2",
"versionType": "semver"
},
{
"status": "affected",
"version": "6.3.10",
"lessThan": "6.4",
"versionType": "semver"
}
],
"programFiles": [
"fs/smb/server/vfs.c"
],
"defaultStatus": "unaffected"
},
{
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"product": "Linux",
"versions": [
{
"status": "affected",
"version": "6.4"
},
{
"status": "unaffected",
"version": "0",
"lessThan": "6.4",
"versionType": "semver"
},
{
"status": "unaffected",
"version": "6.6.160",
"versionType": "semver",
"lessThanOrEqual": "6.6.*"
},
{
"status": "unaffected",
"version": "6.12.114",
"versionType": "semver",
"lessThanOrEqual": "6.12.*"
},
{
"status": "unaffected",
"version": "6.18.57",
"versionType": "semver",
"lessThanOrEqual": "6.18.*"
},
{
"status": "unaffected",
"version": "7.1.4",
"versionType": "semver",
"lessThanOrEqual": "7.1.*"
},
{
"status": "unaffected",
"version": "7.2",
"versionType": "original_commit_for_fix",
"lessThanOrEqual": "*"
}
],
"programFiles": [
"fs/smb/server/vfs.c"
],
"defaultStatus": "affected"
}
]- Related CVEs
- CVE-2026-64400
Source reference:
/cveMetadata/cveId
Publisher severity
high
Source reference: /containers/cna/metrics
- Event
- #46438 · Revision 1
- Added to Heist Feed
- Publisher date