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NVD / CVE Program· CNA Linux

CVE-2021-46979: iio: core: fix ioctl handlers removal

MediumCVSS 5.5 · v3.1—No exploit Fix available

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 11e1cae5da4096552f7c091476cbadbc0d1817da, 901f84de0e16bde10a72d7eb2f2eb73fcde8fa1a, ab6c935ba3a04317632f3b8b68675bdbaf395303.
  • Mentioned 1 time in Turkish national cyber security advisories (siberguvenlik.gov.tr).

Low priority for now. Upgrade to Linux Linux 11e1cae5da4096552f7c091476cbadbc0d1817da, 901f84de0e16bde10a72d7eb2f2eb73fcde8fa1a, ab6c935ba3a04317632f3b8b68675bdbaf395303 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: core: fix ioctl handlers removal Currently ioctl handlers are removed twice. For the first time during iio_device_unregister() then later on inside iio_device_unregister_eventset() and iio_buffers_free_sysfs_and_mask(). Double free leads to kernel panic. Fix this by not touching ioctl handlers list directly but rather letting code responsible for registration call the matching cleanup routine itself.

Published
Feb 28, 2024
Updated
Jun 17, 2026
EPSS
0.2% · 12th 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-2021-46979

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 kernel5.11 and later · before 5.11.22
  • linux linux kernel5.12 and later · before 5.12.5
  • 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

    • 5.11affected
    • 8dedcc3eee3aceb37832176f0a1b03d5687acda3 and later · before 11e1cae5da4096552f7c091476cbadbc0d1817daaffected · git
    • 8dedcc3eee3aceb37832176f0a1b03d5687acda3 and later · before ab6c935ba3a04317632f3b8b68675bdbaf395303affected · git
    • 8dedcc3eee3aceb37832176f0a1b03d5687acda3 and later · before 901f84de0e16bde10a72d7eb2f2eb73fcde8fa1aaffected · git
    • before 5.11not affected · semver
    • 5.11.22 and later · up to and including 5.11.*not affected · semver
    • 5.12.5 and later · up to and including 5.12.*not affected · semver
    • 5.13 and laternot affected · original_commit_for_fix

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-2021-46977Feb 28, 2024 · KVM: VMX: Disable preemption when probing user return MSRs
    22Monitor
  • ← EarlierCVE-2021-46978Feb 28, 2024 · KVM: nVMX: Always make an attempt to map eVMCS after migration
    31Monitor
  • Later →CVE-2021-46980Feb 28, 2024 · usb: typec: ucsi: Retrieve all the PDOs instead of just the first 4
    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 Linux11e1cae5da4096552f7c091476cbadbc0d1817daVendor (CNA)
Linux Linux901f84de0e16bde10a72d7eb2f2eb73fcde8fa1aVendor (CNA)
Linux Linuxab6c935ba3a04317632f3b8b68675bdbaf395303Vendor (CNA)

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-2024-3581479 days apartswiotlb: Fix double-allocation of slots due to broken alignment handling
    35Monitor
  • CVE-2020-367850 days apartmedia: atomisp: Fix use after free in atomisp_alloc_css_stat_bufs()
    31Monitor
  • CVE-2021-469381 days apartdm rq: fix double free of blk_mq_tag_set in dev remove after table load fails
    31Monitor
  • CVE-2021-470825 days aparttun: avoid double free in tun_free_netdev
    31Monitor
  • CVE-2023-524398 days apartuio: Fix use-after-free in uio_open
    31Monitor
  • CVE-2021-4712316 days apartio_uring: fix ltout double free on completion race
    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-415 · Double Free

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.

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 (2 more)

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

All records