NVD / CVE Program· CNA Linux

CVE-2021-47500: iio: mma8452: Fix trigger reference couting

Noroxi assessment

Priority: Monitor (action score 31/100)

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: 0.24% (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 094d513b78b1714113bc016684b8142382e071ba, 794c0898f6bf39a458655d5fb4af70ec43a5cfcb, acf0088ac073ca6e7f4cad6acac112177e08df5e.
Mentioned 1 time in Turkish national cyber security advisories (siberguvenlik.gov.tr).

Low priority for now. Upgrade to Linux Linux 094d513b78b1714113bc016684b8142382e071ba, 794c0898f6bf39a458655d5fb4af70ec43a5cfcb, acf0088ac073ca6e7f4cad6acac112177e08df5e 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: iio: mma8452: Fix trigger reference couting The mma8452 driver directly assigns a trigger to the struct iio_dev. The IIO core when done using this trigger will call `iio_trigger_put()` to drop the reference count by 1. Without the matching `iio_trigger_get()` in the driver the reference count can reach 0 too early, the trigger gets freed while still in use and a use-after-free occurs. Fix this by getting a reference to the trigger before assigning it to the IIO device.

HighCVSS 7.8 · v3.1—No exploit Fix available

Memory safety

BDU:2024-10591

Published: May 24, 2024
Updated: Aug 5, 2026
EPSS: 0.2% · 15th percentile
CWE: CWE-416

Report tools

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Action score

Monitor

Low priority for now.

CVSS: 31 / 40 · 7.8 / 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.

CNA vs NVD score

NVD: 7.8
CNA · Linux: 7.8; agree

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

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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.

Vendor	Product	CPE
linux	linux kernel	cpe:2.3:o:linux:linux_kernel

Affected versions

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

linux linux kernel4.2 and later · before 4.4.295
linux linux kernel4.5 and later · before 4.9.293
linux linux kernel4.10 and later · before 4.14.258
linux linux kernel4.15 and later · before 4.19.221
linux linux kernel4.20 and later · before 5.4.165
linux linux kernel5.5 and later · before 5.10.85
linux linux kernel5.11 and later · before 5.15.8
linux linux kernel5.15

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
- 4.2affected
- ae6d9ce05691bf79694074db7c7da980080548af and later · before 094d513b78b1714113bc016684b8142382e071baaffected · git
- ae6d9ce05691bf79694074db7c7da980080548af and later · before fb75cc4740d81264cd5bcb0e17d961d018a8be96affected · git
- ae6d9ce05691bf79694074db7c7da980080548af and later · before 794c0898f6bf39a458655d5fb4af70ec43a5cfcbaffected · git
- ae6d9ce05691bf79694074db7c7da980080548af and later · before f5deab10ced368c807866283f8b79144c4823be8affected · git
- ae6d9ce05691bf79694074db7c7da980080548af and later · before acf0088ac073ca6e7f4cad6acac112177e08df5eaffected · git
- ae6d9ce05691bf79694074db7c7da980080548af and later · before db12d95085367de8b0223929d1332731024441f1affected · git
- ae6d9ce05691bf79694074db7c7da980080548af and later · before c43517071dfc9fce34f8f69dbb98a86017f6b739affected · git
- ae6d9ce05691bf79694074db7c7da980080548af and later · before cd0082235783f814241a1c9483fb89e405f4f892affected · git
- before 4.2not affected · semver

Package-level exposure

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

Ecosystem	Package	Affected range	Fix
Debian:12	linux	before 5.15.15-1	5.15.15-1

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
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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-2024-36013May 23, 2024 · Bluetooth: L2CAP: Fix slab-use-after-free in l2cap_connect()
35Monitor
← EarlierCVE-2021-47499May 24, 2024 · iio: accel: kxcjk-1013: Fix possible memory leak in probe and remove
22Monitor
Later →CVE-2021-47501May 24, 2024 · i40e: Fix NULL pointer dereference in i40e_dbg_dump_desc
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 / package	Fixed version	Source
Linux Linux	094d513b78b1714113bc016684b8142382e071ba	Vendor (CNA)
Linux Linux	794c0898f6bf39a458655d5fb4af70ec43a5cfcb	Vendor (CNA)
Linux Linux	acf0088ac073ca6e7f4cad6acac112177e08df5e	Vendor (CNA)
Linux Linux	c43517071dfc9fce34f8f69dbb98a86017f6b739	Vendor (CNA)
Linux Linux	cd0082235783f814241a1c9483fb89e405f4f892	Vendor (CNA)
Linux Linux	db12d95085367de8b0223929d1332731024441f1	Vendor (CNA)
Linux Linux	f5deab10ced368c807866283f8b79144c4823be8	Vendor (CNA)
Linux Linux	fb75cc4740d81264cd5bcb0e17d961d018a8be96	Vendor (CNA)
debian:linux	5.15.15-1 · Debian:12	Package 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.

TR-24-0551 · May 27, 2024(Linux Kernel Güncellemesi)

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: high · data can be read
Integrity: high · data or configuration can be modified
Availability: high · the service can be disrupted

Attack vector: Local
Attack complexity: Low
Privileges required: Low
User interaction: None
Scope: Unchanged
Confidentiality impact: High
Integrity impact: High
Availability impact: High

Weakness class (CWE)

CWE-416 · Use After Free

CVSS vector

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

nvd-primary

Root cause

After a memory region is freed, another reference pointing to it is still used. By then, the same region may have been allocated for different data.

The bug in code

The whole CWE-416 class

A representative example of this vulnerability class. Not the vendor's source code; it shows the faulty pattern and its fix.

Vulnerable

1free(dev->buf);
2/* ... another thread is still running ... */
3process(dev->buf);

Fixed

1lock(&dev->lock);
2free(dev->buf);
3dev->buf = NULL;
4unlock(&dev->lock);

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

Fix✗ → ✓Sep 28, 2026, 10:08 PM UTC

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

References

git.kernel.org/stable/c/094d513b78b1714113bc016684b8142382e071ba

Show all references (7 more)

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

All records