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NVD / CVE Program· CNA Linux

CVE-2021-47276: ftrace: Do not blindly read the ip address in ftrace_bug()

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 0bc62e398bbd9e600959e610def5109957437b28, 3e4ddeb68751fb4fb657199aed9cfd5d02796875, 4aedc2bc2b32c93555f47c95610efb89cc1ec09b.
  • Mentioned 1 time in Turkish national cyber security advisories (siberguvenlik.gov.tr).

Low priority for now. Upgrade to Linux Linux 0bc62e398bbd9e600959e610def5109957437b28, 3e4ddeb68751fb4fb657199aed9cfd5d02796875, 4aedc2bc2b32c93555f47c95610efb89cc1ec09b 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: ftrace: Do not blindly read the ip address in ftrace_bug() It was reported that a bug on arm64 caused a bad ip address to be used for updating into a nop in ftrace_init(), but the error path (rightfully) returned -EINVAL and not -EFAULT, as the bug caused more than one error to occur. But because -EINVAL was returned, the ftrace_bug() tried to report what was at the location of the ip address, and read it directly. This caused the machine to panic, as the ip was not pointing to a valid memory address. Instead, read the ip address with copy_from_kernel_nofault() to safely access the memory, and if it faults, report that the address faulted, otherwise report what was in that location.

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-2021-47276

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 kernel2.6.28 and later · before 4.4.273
  • linux linux kernel4.5 and later · before 4.9.273
  • linux linux kernel4.10 and later · before 4.14.237
  • linux linux kernel4.15 and later · before 4.19.195
  • linux linux kernel4.20 and later · before 5.4.126
  • linux linux kernel5.5 and later · before 5.10.44
  • linux linux kernel5.11 and later · before 5.12.11
  • 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

    • 2.6.28affected
    • 05736a427f7e16be948ccbf39782bd3a6ae16b14 and later · before 0bc62e398bbd9e600959e610def5109957437b28affected · git
    • 05736a427f7e16be948ccbf39782bd3a6ae16b14 and later · before 4aedc2bc2b32c93555f47c95610efb89cc1ec09baffected · git
    • 05736a427f7e16be948ccbf39782bd3a6ae16b14 and later · before acf671ba79c1feccc3ec7cfdcffead4efcec49e7affected · git
    • 05736a427f7e16be948ccbf39782bd3a6ae16b14 and later · before 862dcc14f2803c556bdd73b43c27b023fafce2fbaffected · git
    • 05736a427f7e16be948ccbf39782bd3a6ae16b14 and later · before 7e4e824b109f1d41ccf223fbb0565d877d6223a2affected · git
    • 05736a427f7e16be948ccbf39782bd3a6ae16b14 and later · before 97524384762c1fb9b3ded931498dd2047bd0de81affected · git
    • 05736a427f7e16be948ccbf39782bd3a6ae16b14 and later · before 3e4ddeb68751fb4fb657199aed9cfd5d02796875affected · git
    • 05736a427f7e16be948ccbf39782bd3a6ae16b14 and later · before 6c14133d2d3f768e0a35128faac8aa6ed4815051affected · git
    • before 2.6.28not affected · semver

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

Same product

linux: all records

Other highest-scoring records for the same primary product.

  • CVE-2026-31431crypto: algif_aead - Revert to operating out-of-placeKEV
    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-2021-47274May 21, 2024 · tracing: Correct the length check which causes memory corruption
    31Monitor
  • ← EarlierCVE-2021-47275May 21, 2024 · bcache: avoid oversized read request in cache missing code path
    22Monitor
  • Later →CVE-2021-47277May 21, 2024 · kvm: avoid speculation-based attacks from out-of-range memslot accesses
    28Monitor

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 Linux0bc62e398bbd9e600959e610def5109957437b28Vendor (CNA)
Linux Linux3e4ddeb68751fb4fb657199aed9cfd5d02796875Vendor (CNA)
Linux Linux4aedc2bc2b32c93555f47c95610efb89cc1ec09bVendor (CNA)
Linux Linux6c14133d2d3f768e0a35128faac8aa6ed4815051Vendor (CNA)
Linux Linux7e4e824b109f1d41ccf223fbb0565d877d6223a2Vendor (CNA)
Linux Linux862dcc14f2803c556bdd73b43c27b023fafce2fbVendor (CNA)
Linux Linux97524384762c1fb9b3ded931498dd2047bd0de81Vendor (CNA)
Linux Linuxacf671ba79c1feccc3ec7cfdcffead4efcec49e7Vendor (CNA)
debian:linux5.10.46-1 · Debian:12Package 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-2021-472610 days apartIB/mlx5: Fix initializing CQ fragments buffer
    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-706 · Use of Incorrectly-Resolved Name or Reference

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.

Change log

  1. Fix✗ → ✓

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

References

Show all references (7 more)

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

All records