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NVD / CVE Program· CNA Linux

CVE-2021-47227: x86/fpu: Prevent state corruption in __fpu__restore_sig()

Noroxi assessment

Priority: Monitor (action score 22/100)

  • The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
  • Probability of exploitation in the next 30 days: 0.23% (FIRST EPSS).
  • Someone with local access to the system can trigger it. A low-privileged account is enough. No user action is required. No special conditions are required; it is repeatable.
  • Fixed version: Linux Linux 076f732b16a5bf842686e1b43ab6021a2d98233e, 484cea4f362e1eeb5c869abbfb5f90eae6421b38, ec25ea1f3f05d6f8ee51d1277efea986eafd4f2a.
  • Mentioned 1 time in Turkish national cyber security advisories (siberguvenlik.gov.tr).

Low priority for now. Upgrade to Linux Linux 076f732b16a5bf842686e1b43ab6021a2d98233e, 484cea4f362e1eeb5c869abbfb5f90eae6421b38, ec25ea1f3f05d6f8ee51d1277efea986eafd4f2a or later.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

In the Linux kernel, the following vulnerability has been resolved: x86/fpu: Prevent state corruption in __fpu__restore_sig() The non-compacted slowpath uses __copy_from_user() and copies the entire user buffer into the kernel buffer, verbatim. This means that the kernel buffer may now contain entirely invalid state on which XRSTOR will #GP. validate_user_xstate_header() can detect some of that corruption, but that leaves the onus on callers to clear the buffer. Prior to XSAVES support, it was possible just to reinitialize the buffer, completely, but with supervisor states that is not longer possible as the buffer clearing code split got it backwards. Fixing that is possible but not corrupting the state in the first place is more robust. Avoid corruption of the kernel XSAVE buffer by using copy_user_to_xstate() which validates the XSAVE header contents before copying the actual states to the kernel. copy_user_to_xstate() was previously only called for compacted-format kernel buffers, but it works for both compacted and non-compacted forms. Using it for the non-compacted form is slower because of multiple __copy_from_user() operations, but that cost is less important than robust code in an already slow path. [ Changelog polished by Dave Hansen ]

MediumCVSS 5.5 · v3.1—No exploit Fix available
Published
May 21, 2024
Updated
Jun 17, 2026
EPSS
0.2% · 14th percentile

Report tools

JSON

Action score

22

Monitor

Low priority for now.

CVSS
22 / 40 · 5.5 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.2%

CISA SSVC decision

Exploitation
none
Automatable
no
Technical impact
partial

Vulnrichment: CISA's decision-tree inputs.

Get told when this record changes

  • Not in KEV: no record of exploitation in the wild
  • No public exploit code on record
  • A fix has been released

If any of these changes, we'll tell you in the daily email digest.

Follow CVE-2021-47227

When you'll hear from us

  • when it enters CISA KEV
  • when exploit code appears or is weaponized
  • when the record is updated (including a fixed version)
  • when EPSS rises 20 points in a week

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Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

VendorProduct
linuxlinux kernel

Affected versions

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

  • linux linux kernel5.8 and later · before 5.10.46
  • linux linux kernel5.11 and later · before 5.12.13
  • linux linux kernel5.13

Versions reported by the vendor

Affected version ranges reported by the assigning authority (Linux). Independent of NVD's CPE analysis and usually ahead of it.

  • Linux Linux

    • 5.8affected
    • b860eb8dce5906b14e3a7f3c771e0b3d6ef61b94 and later · before 076f732b16a5bf842686e1b43ab6021a2d98233eaffected · git
    • b860eb8dce5906b14e3a7f3c771e0b3d6ef61b94 and later · before ec25ea1f3f05d6f8ee51d1277efea986eafd4f2aaffected · git
    • b860eb8dce5906b14e3a7f3c771e0b3d6ef61b94 and later · before 484cea4f362e1eeb5c869abbfb5f90eae6421b38affected · git
    • before 5.8not affected · semver
    • 5.10.46 and later · up to and including 5.10.*not affected · semver
    • 5.12.13 and later · up to and including 5.12.*not affected · semver
    • 5.13 and laternot affected · original_commit_for_fix

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

EcosystemPackageAffected rangeFix
Debian:12linuxbefore 5.10.46-15.10.46-1
SUSE:Linux Enterprise High Performance Computing 15 SP3-LTSSkernel-64kbbefore 5.3.18-150300.59.164.15.3.18-150300.59.164.1
SUSE:Linux Enterprise High Performance Computing 15 SP3-LTSSkernel-default-basebefore 5.3.18-150300.59.164.1.150300.18.96.15.3.18-150300.59.164.1.150300.18.96.1
SUSE:Linux Enterprise High Performance Computing 15 SP3-LTSSkernel-docsbefore 5.3.18-150300.59.164.15.3.18-150300.59.164.1
SUSE:Linux Enterprise High Performance Computing 15 SP3-LTSSkernel-obs-buildbefore 5.3.18-150300.59.164.15.3.18-150300.59.164.1
SUSE:Linux Enterprise High Performance Computing 15 SP3-LTSSkernel-preemptbefore 5.3.18-150300.59.164.15.3.18-150300.59.164.1
SUSE:Linux Enterprise High Performance Computing 15 SP3-LTSSkernel-sourcebefore 5.3.18-150300.59.164.15.3.18-150300.59.164.1
SUSE:Linux Enterprise High Performance Computing 15 SP3-LTSSkernel-symsbefore 5.3.18-150300.59.164.15.3.18-150300.59.164.1
SUSE:Linux Enterprise Live Patching 15 SP3kernel-defaultbefore 5.3.18-150300.59.164.15.3.18-150300.59.164.1
SUSE:Linux Enterprise Live Patching 15 SP3kernel-livepatch-SLE15-SP3_Update_45before 1-150300.7.3.11-150300.7.3.1
SUSE:Linux Enterprise Micro 5.1kernel-rtbefore 5.3.18-150300.172.15.3.18-150300.172.1
SUSE:Linux Enterprise Micro 5.1kernel-source-rtbefore 5.3.18-150300.172.15.3.18-150300.172.1
SUSE:Linux Enterprise Server 15 SP3-LTSSkernel-zfcpdumpbefore 5.3.18-150300.59.164.15.3.18-150300.59.164.1

Same product

linux: all records

Other highest-scoring records for the same primary product.

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    90Now
  • CVE-2022-0847A flaw was found in the way the "flags" member of the new pipe buffer structure was lacking proper initialization in copy_page_to_iter_pipe KEV
    89Now
  • CVE-2021-22555Heap Out-Of-Bounds Write in Netfilter IP6T_SO_SET_REPLACEKEV
    85Now

Published before and after this one in the same product

  • ← EarlierCVE-2021-47225May 21, 2024 · mac80211: fix deadlock in AP/VLAN handling
    22Monitor
  • ← EarlierCVE-2021-47226May 21, 2024 · x86/fpu: Invalidate FPU state after a failed XRSTOR from a user buffer
    28Monitor
  • Later →CVE-2021-47228May 21, 2024 · x86/ioremap: Map EFI-reserved memory as encrypted for SEV
    24Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / packageFixed versionSource
Linux Linux076f732b16a5bf842686e1b43ab6021a2d98233eVendor (CNA)
Linux Linux484cea4f362e1eeb5c869abbfb5f90eae6421b38Vendor (CNA)
Linux Linuxec25ea1f3f05d6f8ee51d1277efea986eafd4f2aVendor (CNA)
debian:linux5.10.46-1 · Debian:12Package registry (OSV)
suse:kernel-64kb5.3.18-150300.59.164.1 · SUSE:Linux Enterprise High Performance Computing 15 SP3-LTSSPackage registry (OSV)
suse:kernel-default5.3.18-150300.59.164.1 · SUSE:Linux Enterprise Live Patching 15 SP3Package registry (OSV)
suse:kernel-default-base5.3.18-150300.59.164.1.150300.18.96.1 · SUSE:Linux Enterprise High Performance Computing 15 SP3-LTSSPackage registry (OSV)
suse:kernel-docs5.3.18-150300.59.164.1 · SUSE:Linux Enterprise High Performance Computing 15 SP3-LTSSPackage registry (OSV)
suse:kernel-livepatch-SLE15-SP3_Update_451-150300.7.3.1 · SUSE:Linux Enterprise Live Patching 15 SP3Package registry (OSV)
suse:kernel-obs-build5.3.18-150300.59.164.1 · SUSE:Linux Enterprise High Performance Computing 15 SP3-LTSSPackage registry (OSV)
suse:kernel-preempt5.3.18-150300.59.164.1 · SUSE:Linux Enterprise High Performance Computing 15 SP3-LTSSPackage registry (OSV)
suse:kernel-rt5.3.18-150300.172.1 · SUSE:Linux Enterprise Micro 5.1Package registry (OSV)
suse:kernel-source5.3.18-150300.59.164.1 · SUSE:Linux Enterprise High Performance Computing 15 SP3-LTSSPackage registry (OSV)
suse:kernel-source-rt5.3.18-150300.172.1 · SUSE:Linux Enterprise Micro 5.1Package registry (OSV)
suse:kernel-syms5.3.18-150300.59.164.1 · SUSE:Linux Enterprise High Performance Computing 15 SP3-LTSSPackage registry (OSV)
suse:kernel-zfcpdump5.3.18-150300.59.164.1 · SUSE:Linux Enterprise Server 15 SP3-LTSSPackage registry (OSV)

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

No dated events beyond publication.

No history yet (it accumulates with the daily EPSS job).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

No commit or PR link among the references.

Credits

All researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

No credits in the CNA record.

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

  • CVE-2025-39682472 days aparttls: fix handling of zero-length records on the rx_listKEV
    70This week
  • CVE-2024-4215970 days apartscsi: mpi3mr: Sanitise num_phys
    31Monitor
  • CVE-2024-4216070 days apartf2fs: check validation of fault attrs in f2fs_build_fault_attr()
    31Monitor
  • CVE-2021-4701483 days apartnet/sched: act_ct: fix wild memory access when clearing fragments
    31Monitor
  • CVE-2024-4228488 days aparttipc: Return non-zero value from tipc_udp_addr2str() on error
    31Monitor
  • CVE-2024-47727153 days apartx86/tdx: Fix "in-kernel MMIO" check
    31Monitor

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

—

Bug bounty scope

No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).

National notice (Türkiye Cybersecurity Directorate / USOM)

Official security notices citing this record; remediation advice is on the agency's page.

All national notices →

Technical details

Attack conditions

  • Someone with local access to the system can trigger it.
  • A low-privileged account is enough.
  • No user action is required.
  • No special conditions are required; it is repeatable.

If successful

Confidentiality
none
Integrity
none
Availability
high · the service can be disrupted
Attack vector
Local
Attack complexity
Low
Privileges required
Low
User interaction
None
Scope
Unchanged
Confidentiality impact
None
Integrity impact
None
Availability impact
High

Weakness class (CWE)

CWE-754 · Improper Check for Unusual or Exceptional Conditions

CVSS vector

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

nvd-primary

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

MITRE has no CAPEC/ATT&CK mapping for this CWE.

Change log

  1. Fix✗ → ✓

For records you follow, these changes also arrive as notifications. →

References

Show all references (2 more)

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records