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NVD / CVE Program· CNA Linux

CVE-2021-47170: USB: usbfs: Don't WARN about excessively large memory allocations

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 2ab21d6e1411999b5fb43434f421f00bf50002eb, 2c835fede13e03f2743a333e4370b5ed2db91e83, 4f2629ea67e7225c3fd292c7fe4f5b3c9d6392de.

Low priority for now. Upgrade to Linux Linux 2ab21d6e1411999b5fb43434f421f00bf50002eb, 2c835fede13e03f2743a333e4370b5ed2db91e83, 4f2629ea67e7225c3fd292c7fe4f5b3c9d6392de 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: USB: usbfs: Don't WARN about excessively large memory allocations Syzbot found that the kernel generates a WARNing if the user tries to submit a bulk transfer through usbfs with a buffer that is way too large. This isn't a bug in the kernel; it's merely an invalid request from the user and the usbfs code does handle it correctly. In theory the same thing can happen with async transfers, or with the packet descriptor table for isochronous transfers. To prevent the MM subsystem from complaining about these bad allocation requests, add the __GFP_NOWARN flag to the kmalloc calls for these buffers.

MediumCVSS 5.5 · v3.1—No exploit Fix available
Published
Mar 25, 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-2021-47170

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 4.19.193
  • linux linux kernel4.20 and later · before 5.4.124
  • linux linux kernel5.5 and later · before 5.10.42
  • linux linux kernel5.11 and later · before 5.12.9
  • 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

    • 3.3affected
    • add1aaeabe6b08ed26381a2a06e505b2f09c3ba5 and later · before 2ab21d6e1411999b5fb43434f421f00bf50002ebaffected · git
    • add1aaeabe6b08ed26381a2a06e505b2f09c3ba5 and later · before 2c835fede13e03f2743a333e4370b5ed2db91e83affected · git
    • add1aaeabe6b08ed26381a2a06e505b2f09c3ba5 and later · before 8d83f109e920d2776991fa142bb904d985dca2edaffected · git
    • add1aaeabe6b08ed26381a2a06e505b2f09c3ba5 and later · before 9f7cb3f01a10d9064cf13b3d26fb7e7a5827d098affected · git
    • add1aaeabe6b08ed26381a2a06e505b2f09c3ba5 and later · before 4f2629ea67e7225c3fd292c7fe4f5b3c9d6392deaffected · git
    • before 3.3not affected · semver
    • 4.19.193 and later · up to and including 4.19.*not affected · semver
    • 5.4.124 and later · up to and including 5.4.*not affected · semver
    • 5.10.42 and later · up to and including 5.10.*not affected · semver

Package-level exposure

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

EcosystemPackageAffected rangeFix
Debian:12linuxbefore 5.14.6-15.14.6-1
SUSE:Linux Enterprise Live Patching 12 SP5kernel-defaultbefore 4.12.14-122.261.14.12.14-122.261.1
SUSE:Linux Enterprise Live Patching 12 SP5kgraft-patch-SLE12-SP5_Update_69before 1-8.3.11-8.3.1
SUSE:Linux Enterprise Server 12 SP5-LTSSkernel-sourcebefore 4.12.14-122.261.14.12.14-122.261.1
SUSE:Linux Enterprise Server 12 SP5-LTSSkernel-symsbefore 4.12.14-122.261.14.12.14-122.261.1

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-2021-47168Mar 25, 2024 · NFS: fix an incorrect limit in filelayout_decode_layout()
    22Monitor
  • ← EarlierCVE-2021-47169Mar 25, 2024 · serial: rp2: use 'request_firmware' instead of 'request_firmware_nowait'
    22Monitor
  • Later →CVE-2021-47171Mar 25, 2024 · net: usb: fix memory leak in smsc75xx_bind
    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 Linux2ab21d6e1411999b5fb43434f421f00bf50002ebVendor (CNA)
Linux Linux2c835fede13e03f2743a333e4370b5ed2db91e83Vendor (CNA)
Linux Linux4f2629ea67e7225c3fd292c7fe4f5b3c9d6392deVendor (CNA)
Linux Linux8d83f109e920d2776991fa142bb904d985dca2edVendor (CNA)
Linux Linux9f7cb3f01a10d9064cf13b3d26fb7e7a5827d098Vendor (CNA)
debian:linux5.14.6-1 · Debian:12Package registry (OSV)
suse:kernel-default4.12.14-122.261.1 · SUSE:Linux Enterprise Live Patching 12 SP5Package registry (OSV)
suse:kernel-source4.12.14-122.261.1 · SUSE:Linux Enterprise Server 12 SP5-LTSSPackage registry (OSV)
suse:kernel-syms4.12.14-122.261.1 · SUSE:Linux Enterprise Server 12 SP5-LTSSPackage registry (OSV)
suse:kgraft-patch-SLE12-SP5_Update_691-8.3.1 · SUSE:Linux Enterprise Live Patching 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.

  • CVE-2021-471370 days apartnet: lantiq: fix memory corruption in RX ring
    39Monitor
  • CVE-2024-3596956 days apartipv6: fix race condition between ipv6_get_ifaddr and ipv6_del_addr
    35Monitor
  • CVE-2021-4755160 days apartdrm/amd/amdkfd: Fix kernel panic when reset failed and been triggered again
    31Monitor
  • CVE-2024-3402791 days apartf2fs: compress: fix to cover {reserve,release}_compress_blocks() w/ cp_rwsem lock
    31Monitor
  • CVE-2021-4713010 days apartnvmet: fix freeing unallocated p2pmem
    30Monitor
  • CVE-2023-5252923 days apartHID: sony: Fix a potential memory leak in sony_probe()
    24Monitor

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).

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-770 · Allocation of Resources Without Limits or Throttling

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 (4 more)

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

All records