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NVD / CVE Program· CNA Linux

CVE-2021-47231: can: mcba_usb: fix memory leak in mcba_usb

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: 0.22% (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 6bd3d80d1f019cefa7011056c54b323f1d8b8e83, 6f87c0e21ad20dd3d22108e33db1c552dfa352a0, 89df95ce32be204eef2e7d4b2f6fb552fb191a68.
  • Mentioned 1 time in Turkish national cyber security advisories (siberguvenlik.gov.tr).

Low priority for now. Upgrade to Linux Linux 6bd3d80d1f019cefa7011056c54b323f1d8b8e83, 6f87c0e21ad20dd3d22108e33db1c552dfa352a0, 89df95ce32be204eef2e7d4b2f6fb552fb191a68 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: can: mcba_usb: fix memory leak in mcba_usb Syzbot reported memory leak in SocketCAN driver for Microchip CAN BUS Analyzer Tool. The problem was in unfreed usb_coherent. In mcba_usb_start() 20 coherent buffers are allocated and there is nothing, that frees them: 1) In callback function the urb is resubmitted and that's all 2) In disconnect function urbs are simply killed, but URB_FREE_BUFFER is not set (see mcba_usb_start) and this flag cannot be used with coherent buffers. Fail log: | [ 1354.053291][ T8413] mcba_usb 1-1:0.0 can0: device disconnected | [ 1367.059384][ T8420] kmemleak: 20 new suspected memory leaks (see /sys/kernel/debug/kmem) So, all allocated buffers should be freed with usb_free_coherent() explicitly NOTE: The same pattern for allocating and freeing coherent buffers is used in drivers/net/can/usb/kvaser_usb/kvaser_usb_core.c

MediumCVSS 5.5 · v3.1—No exploit Fix available
Published
May 21, 2024
Updated
Jun 17, 2026
EPSS
0.2% · 13th 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-2021-47231

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 kernel4.12 and later · before 4.14.238
  • linux linux kernel4.15 and later · before 4.19.196
  • linux linux kernel4.20 and later · before 5.4.128
  • linux linux kernel5.5 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

    • 4.12affected
    • 51f3baad7de943780ce0c17bd7975df567dd6e14 and later · before 89df95ce32be204eef2e7d4b2f6fb552fb191a68affected · git
    • 51f3baad7de943780ce0c17bd7975df567dd6e14 and later · before a115198caaab6d663bef75823a3c5f0802306d60affected · git
    • 51f3baad7de943780ce0c17bd7975df567dd6e14 and later · before 6f87c0e21ad20dd3d22108e33db1c552dfa352a0affected · git
    • 51f3baad7de943780ce0c17bd7975df567dd6e14 and later · before 6bd3d80d1f019cefa7011056c54b323f1d8b8e83affected · git
    • 51f3baad7de943780ce0c17bd7975df567dd6e14 and later · before d0760a4ef85697bc756d06eae17ae27f3f055401affected · git
    • 51f3baad7de943780ce0c17bd7975df567dd6e14 and later · before 91c02557174be7f72e46ed7311e3bea1939840b0affected · git
    • before 4.12not affected · semver
    • 4.14.238 and later · up to and including 4.14.*not affected · semver
    • 4.19.196 and later · up to and including 4.19.*not 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
SUSE:Linux Enterprise High Availability Extension 12 SP5kernel-defaultbefore 4.12.14-122.219.14.12.14-122.219.1
SUSE:Linux Enterprise High Performance Computing 15 SP2-LTSSkernel-default-basebefore 5.3.18-150200.24.194.1.150200.9.99.15.3.18-150200.24.194.1.150200.9.99.1
SUSE:Linux Enterprise High Performance Computing 15 SP2-LTSSkernel-docsbefore 5.3.18-150200.24.194.15.3.18-150200.24.194.1
SUSE:Linux Enterprise High Performance Computing 15 SP2-LTSSkernel-obs-buildbefore 5.3.18-150200.24.194.15.3.18-150200.24.194.1
SUSE:Linux Enterprise High Performance Computing 15 SP2-LTSSkernel-preemptbefore 5.3.18-150200.24.194.15.3.18-150200.24.194.1
SUSE:Linux Enterprise High Performance Computing 15 SP2-LTSSkernel-sourcebefore 5.3.18-150200.24.194.15.3.18-150200.24.194.1
SUSE:Linux Enterprise High Performance Computing 15 SP2-LTSSkernel-symsbefore 5.3.18-150200.24.194.15.3.18-150200.24.194.1
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 12 SP5kgraft-patch-SLE12-SP5_Update_57before 1-8.3.11-8.3.1
SUSE:Linux Enterprise Live Patching 15 SP2kernel-defaultbefore 5.3.18-150200.24.194.15.3.18-150200.24.194.1
SUSE:Linux Enterprise Live Patching 15 SP2kernel-livepatch-SLE15-SP2_Update_49before 1-150200.5.3.11-150200.5.3.1
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-rtbefore 5.3.18-150300.211.15.3.18-150300.211.1
SUSE:Linux Enterprise Micro 5.1kernel-source-rtbefore 5.3.18-150300.211.15.3.18-150300.211.1
SUSE:Linux Enterprise Micro 5.1kernel-source-rtbefore 5.3.18-150300.172.15.3.18-150300.172.1

+12

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-2021-47229May 21, 2024 · PCI: aardvark: Fix kernel panic during PIO transfer
    22Monitor
  • ← EarlierCVE-2021-47230May 21, 2024 · KVM: x86: Immediately reset the MMU context when the SMM flag is cleared
    26Monitor
  • Later →CVE-2021-47232May 21, 2024 · can: j1939: fix Use-after-Free, hold skb ref while in use
    39Monitor

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 Linux6bd3d80d1f019cefa7011056c54b323f1d8b8e83Vendor (CNA)
Linux Linux6f87c0e21ad20dd3d22108e33db1c552dfa352a0Vendor (CNA)
Linux Linux89df95ce32be204eef2e7d4b2f6fb552fb191a68Vendor (CNA)
Linux Linux91c02557174be7f72e46ed7311e3bea1939840b0Vendor (CNA)
Linux Linuxa115198caaab6d663bef75823a3c5f0802306d60Vendor (CNA)
Linux Linuxd0760a4ef85697bc756d06eae17ae27f3f055401Vendor (CNA)
debian:linux5.10.46-1 · Debian:12Package registry (OSV)
suse:kernel-azure4.12.14-16.188.1 · SUSE:Linux Enterprise Server 12 SP5Package registry (OSV)
suse:kernel-default5.3.18-150200.24.194.1 · SUSE:Linux Enterprise Live Patching 15 SP2Package registry (OSV)
suse:kernel-default-base5.3.18-150200.24.194.1.150200.9.99.1 · SUSE:Linux Enterprise High Performance Computing 15 SP2-LTSSPackage registry (OSV)
suse:kernel-docs5.3.18-150200.24.194.1 · SUSE:Linux Enterprise High Performance Computing 15 SP2-LTSSPackage registry (OSV)
suse:kernel-livepatch-SLE15-SP2_Update_491-150200.5.3.1 · SUSE:Linux Enterprise Live Patching 15 SP2Package registry (OSV)
suse:kernel-obs-build5.3.18-150200.24.194.1 · SUSE:Linux Enterprise High Performance Computing 15 SP2-LTSSPackage registry (OSV)
suse:kernel-rt4.12.14-10.188.1 · SUSE:Linux Enterprise Real Time 12 SP5Package registry (OSV)
suse:kernel-rt_debug4.12.14-10.188.1 · SUSE:Linux Enterprise Real Time 12 SP5Package registry (OSV)
suse:kernel-source-azure4.12.14-16.188.1 · SUSE:Linux Enterprise Server 12 SP5Package registry (OSV)
suse:kernel-source-rt4.12.14-10.188.1 · SUSE:Linux Enterprise Real Time 12 SP5Package registry (OSV)
suse:kernel-syms-azure4.12.14-16.188.1 · SUSE:Linux Enterprise Server 12 SP5Package registry (OSV)
suse:kernel-syms-rt4.12.14-10.188.1 · 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
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-401 · Missing Release of Memory after Effective Lifetime

CVSS vector

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

nvd-secondary

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 (5 more)

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

All records