{
  "threat_severity" : "Low",
  "public_date" : "2024-05-21T00:00:00Z",
  "bugzilla" : {
    "description" : "kernel: x86/fpu: Invalidate FPU state after a failed XRSTOR from a user buffer",
    "id" : "2282591",
    "url" : "https://bugzilla.redhat.com/show_bug.cgi?id=2282591"
  },
  "cvss3" : {
    "cvss3_base_score" : "5.5",
    "cvss3_scoring_vector" : "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H",
    "status" : "verified"
  },
  "cwe" : "CWE-402",
  "details" : [ "In the Linux kernel, the following vulnerability has been resolved:\nx86/fpu: Invalidate FPU state after a failed XRSTOR from a user buffer\nBoth Intel and AMD consider it to be architecturally valid for XRSTOR to\nfail with #PF but nonetheless change the register state.  The actual\nconditions under which this might occur are unclear [1], but it seems\nplausible that this might be triggered if one sibling thread unmaps a page\nand invalidates the shared TLB while another sibling thread is executing\nXRSTOR on the page in question.\n__fpu__restore_sig() can execute XRSTOR while the hardware registers\nare preserved on behalf of a different victim task (using the\nfpu_fpregs_owner_ctx mechanism), and, in theory, XRSTOR could fail but\nmodify the registers.\nIf this happens, then there is a window in which __fpu__restore_sig()\ncould schedule out and the victim task could schedule back in without\nreloading its own FPU registers. This would result in part of the FPU\nstate that __fpu__restore_sig() was attempting to load leaking into the\nvictim task's user-visible state.\nInvalidate preserved FPU registers on XRSTOR failure to prevent this\nsituation from corrupting any state.\n[1] Frequent readers of the errata lists might imagine \"complex\nmicroarchitectural conditions\"." ],
  "affected_release" : [ {
    "product_name" : "Red Hat Enterprise Linux 8",
    "release_date" : "2021-11-09T00:00:00Z",
    "advisory" : "RHSA-2021:4356",
    "cpe" : "cpe:/o:redhat:enterprise_linux:8",
    "package" : "kernel-0:4.18.0-348.el8"
  } ],
  "package_state" : [ {
    "product_name" : "Red Hat Enterprise Linux 6",
    "fix_state" : "Not affected",
    "package_name" : "kernel",
    "cpe" : "cpe:/o:redhat:enterprise_linux:6"
  }, {
    "product_name" : "Red Hat Enterprise Linux 7",
    "fix_state" : "Not affected",
    "package_name" : "kernel",
    "cpe" : "cpe:/o:redhat:enterprise_linux:7"
  }, {
    "product_name" : "Red Hat Enterprise Linux 7",
    "fix_state" : "Not affected",
    "package_name" : "kernel-rt",
    "cpe" : "cpe:/o:redhat:enterprise_linux:7"
  }, {
    "product_name" : "Red Hat Enterprise Linux 8",
    "fix_state" : "Fix deferred",
    "package_name" : "kernel-rt",
    "cpe" : "cpe:/o:redhat:enterprise_linux:8"
  }, {
    "product_name" : "Red Hat Enterprise Linux 9",
    "fix_state" : "Fix deferred",
    "package_name" : "kernel",
    "cpe" : "cpe:/o:redhat:enterprise_linux:9"
  }, {
    "product_name" : "Red Hat Enterprise Linux 9",
    "fix_state" : "Fix deferred",
    "package_name" : "kernel-rt",
    "cpe" : "cpe:/o:redhat:enterprise_linux:9"
  } ],
  "references" : [ "https://www.cve.org/CVERecord?id=CVE-2021-47226\nhttps://nvd.nist.gov/vuln/detail/CVE-2021-47226\nhttps://lore.kernel.org/linux-cve-announce/2024052137-CVE-2021-47226-5d4f@gregkh/T" ],
  "name" : "CVE-2021-47226",
  "csaw" : false
}