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NVD / CVE Program· CNA Linux

CVE-2021-47620: Bluetooth: refactor malicious adv data check

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: 0.32% (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 305e92f525450f3e1b5f5c9dc7eadb152d66a082, 4.14.265, 4.19.228.
  • Severity is disputed: the assigning authority (CNA) scores it 8.1, NVD 5.5.
  • Mentioned 1 time in Turkish national cyber security advisories (siberguvenlik.gov.tr).

Low priority for now. Upgrade to Linux Linux 305e92f525450f3e1b5f5c9dc7eadb152d66a082, 4.14.265, 4.19.228 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: Bluetooth: refactor malicious adv data check Check for out-of-bound read was being performed at the end of while num_reports loop, and would fill journal with false positives. Added check to beginning of loop processing so that it doesn't get checked after ptr has been advanced.

MediumCVSS 5.5 · v3.1—No exploit Fix available
Published
Jun 20, 2024
Updated
Aug 5, 2026
EPSS
0.3% · 25th 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 · 0.3%

CISA SSVC decision

Exploitation
none
Automatable
no
Technical impact
partial

Vulnrichment: CISA's decision-tree inputs.

CNA vs NVD score

NVD
5.5
CNA · Linux
8.1
2.6 point gap

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

The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.

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-2021-47620

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 kernelbefore 4.4.302
  • linux linux kernel4.5 and later · before 4.9.300
  • linux linux kernel4.10 and later · before 4.14.265
  • linux linux kernel4.15 and later · before 4.19.228
  • linux linux kernel4.20 and later · before 5.4.176
  • linux linux kernel5.5 and later · before 5.10.96
  • linux linux kernel5.11 and later · before 5.15.19
  • linux linux kernel5.16 and later · before 5.16.5

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

    • 048acfa4daf167b007b6bd8bef474e90c2282a5f and later · before 305e92f525450f3e1b5f5c9dc7eadb152d66a082affected · git
    • 7d4238edd3bf8b8c75571cc3b382bc10438ac588 and later · before 7889b38a7f21ed19314f83194622b195d328465caffected · git
    • 185c77cbb53bc7481acc5a0b4e6119bbe393d561 and later · before 5a539c08d743d9910631448da78af5e961664c0eaffected · git
    • 4a1491432394b22e585a185ffca49086e4046aae and later · before 8819f93cd4a443dfe547aa622b21f723757df3fbaffected · git
    • 24161b9c43de966789d5956428f45002d10f878e and later · before 835d3706852537bf92eb23eb8635b8dee0c0aa67affected · git
    • ffc9019bd991707701273c2e5d8aed472229fc4d and later · before 83d5196b65d1b29e27d7dd16a3b9b439fb1d2dbaaffected · git
    • 2de0e6a71ceb056e17e4684dce8b7640367996f9 and later · before bcea886771c3f22a590c8c8b9139a107bd7f1e1caffected · git
    • 640a476e38fce6c70c738ac09e5167e34f570303 and later · before 5c968affa804ba98c3c603f37ffea6fba618025eaffected · git
    • 3a56ef719f0b9682afb8a86d64b2399e36faa4e6 and later · before 899663be5e75dc0174dc8bda0b5e6826edf0b29aaffected · git
    • 4.4.300 and later · before 4.4.302affected · semver

Package-level exposure

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

EcosystemPackageAffected rangeFix
Debian:12linuxbefore 5.16.7-15.16.7-1
SUSE:Linux Enterprise Real Time 12 SP5kernel-rtbefore 4.12.14-10.203.14.12.14-10.203.1
SUSE:Linux Enterprise Real Time 12 SP5kernel-rt_debugbefore 4.12.14-10.203.14.12.14-10.203.1
SUSE:Linux Enterprise Real Time 12 SP5kernel-source-rtbefore 4.12.14-10.203.14.12.14-10.203.1
SUSE:Linux Enterprise Real Time 12 SP5kernel-syms-rtbefore 4.12.14-10.203.14.12.14-10.203.1

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-2021-47618Jun 20, 2024 · ARM: 9170/1: fix panic when kasan and kprobe are enabled
    22Monitor
  • ← EarlierCVE-2021-47619Jun 20, 2024 · i40e: Fix queues reservation for XDP
    22Monitor
  • Later →CVE-2022-48711Jun 20, 2024 · tipc: improve size validations for received domain records
    22Monitor

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 Linux305e92f525450f3e1b5f5c9dc7eadb152d66a082Vendor (CNA)
Linux Linux4.14.265Vendor (CNA)
Linux Linux4.19.228Vendor (CNA)
Linux Linux4.4.302Vendor (CNA)
Linux Linux4.9.300Vendor (CNA)
Linux Linux5.10.96Vendor (CNA)
Linux Linux5.15.19Vendor (CNA)
Linux Linux5.16.5Vendor (CNA)
Linux Linux5.4.176Vendor (CNA)
Linux Linux5a539c08d743d9910631448da78af5e961664c0eVendor (CNA)
Linux Linux5c968affa804ba98c3c603f37ffea6fba618025eVendor (CNA)
Linux Linux7889b38a7f21ed19314f83194622b195d328465cVendor (CNA)
Linux Linux835d3706852537bf92eb23eb8635b8dee0c0aa67Vendor (CNA)
Linux Linux83d5196b65d1b29e27d7dd16a3b9b439fb1d2dbaVendor (CNA)
Linux Linux8819f93cd4a443dfe547aa622b21f723757df3fbVendor (CNA)
Linux Linux899663be5e75dc0174dc8bda0b5e6826edf0b29aVendor (CNA)
Linux Linuxbcea886771c3f22a590c8c8b9139a107bd7f1e1cVendor (CNA)
debian:linux5.16.7-1 · Debian:12Package registry (OSV)
suse:kernel-rt4.12.14-10.203.1 · SUSE:Linux Enterprise Real Time 12 SP5Package registry (OSV)
suse:kernel-rt_debug4.12.14-10.203.1 · SUSE:Linux Enterprise Real Time 12 SP5Package registry (OSV)
suse:kernel-source-rt4.12.14-10.203.1 · SUSE:Linux Enterprise Real Time 12 SP5Package registry (OSV)
suse:kernel-syms-rt4.12.14-10.203.1 · SUSE:Linux Enterprise Real Time 12 SP5Package 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.

No nightly-computed relations.

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
high · data or configuration can be modified
Availability
none
Attack vector
Local
Attack complexity
Low
Privileges required
Low
User interaction
None
Scope
Unchanged
Confidentiality impact
None
Integrity impact
High
Availability impact
None

Weakness class (CWE)

CWE-125 · Out-of-bounds Read

CVSS vector

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

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.

ATT&CK techniques

—

Change log

  1. Fix✗ → ✓

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

References

Show all references (8 more)

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

All records