fs: preserve ACL_DONT_CACHE state in forget_cached_acl()

{
  "id": "89474c779cffbd3e921dffd8e109a497f2b42746146709a359080f1891d74679",
  "url": "https://osv.dev/vulnerability/CVE-2026-68149",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "fs: preserve ACL_DONT_CACHE state in forget_cached_acl()",
    "summary": "In the Linux kernel, the following vulnerability has been resolved: fs: preserve ACL_DONT_CACHE state in forget_cached_acl() The ACL_DONT_CACHE state is meant to be a constant state for the inode for filesystems that want to opt out of posix acl caching. Commit facd61053cff1 (\"fuse: fixes after adapting to new posix acl api\") used this facility to opt out of posix acl caching for fuse inodes with fuse server that does not negotiate FUSE_POSIX_ACL (fc->posix_acl). The commit also takes care to gate the forget_all_cached_acls() call in fuse_set_acl() on fc->posix_acl because there is no need for it, but there are other placed in fuse code which call forget_all_cached_acls() unconditional to fc->posix_acl and those cause the loss of the ACL_DONT_CACHE state. This is not only a functional bug. Properly timed, a get_acl() from this fuse filesystem can return a stale cached value, as was observed in tests, because set_acl() does not invalidate the unintentional acl cache. We could fix this in fuse, but it actually makes no sense for the vfs helper forget_cached_acl() to invalidate the ACL_DONT_CACHE state, so let it not do that to fix fuse and future users of ACL_DONT_CACHE.",
    "evidence": "osv:CVE-2026-68149",
    "products": [
      {
        "name": {
          "value": "Kernel",
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        "prerequisites": [],
        "fixed_versions": [
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    "severity": "high",
    "structured": {
      "id": "CVE-2026-68149",
      "aliases": [
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      "metrics": [
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          "type": "CVSS_V3",
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      "modified": "2026-10-28T02:30:50.552560090Z",
      "provider": "osv",
      "references": [
        "https://git.kernel.org/stable/c/4b9a5458d02e214ef2b384124ca626e3e381d778",
        "https://git.kernel.org/stable/c/834ddf899484a2f23129080e8773bc04f4691d07",
        "https://git.kernel.org/stable/c/a019b074903b3ad0a9726087efd0e8291452023b",
        "https://git.kernel.org/stable/c/b98fad81f1202b0eb26aacf3ff4cc7a21ed3b5bf",
        "https://git.kernel.org/stable/c/ca03a7984a34f48085fd013e0d2cf4e6420b4acf",
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/68xxx/CVE-2026-68149.json",
        "https://nvd.nist.gov/vuln/detail/CVE-2026-68149",
        "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"
      ],
      "provider_metadata": {
        "cna_assigner": "Linux",
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    "severity_evidence": "/severity/0/score"
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  "source_id": "core-osv",
  "document_id": 519077,
  "published_at": "2026-08-10T11:59:14.645+00:00"
}