CVE-2021-47530

Local denial of service via submitqueue reference leak

Published May 24, 2024 · Updated May 11, 2026

A reference leak in Linux 5.15 through 5.15.6 allows local users to exhaust kernel memory through the MSM wait-fence ioctl. In msm_ioctl_wait_fence(), the already-signaled-fence return path fails to release the submitqueue reference acquired for the caller's queue. A local low-privilege process with access to the MSM DRM render device can repeat the ioctl to retain references, exhaust kernel memory, and interrupt service.

CVSS severity5.5
Medium
EPSS probability0.21%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

A reference leak in Linux 5.15 through 5.15.6 allows local users to exhaust kernel memory through the MSM wait-fence ioctl. In msm_ioctl_wait_fence(), the already-signaled-fence return path fails to release the submitqueue reference acquired for the caller's queue. A local low-privilege process with access to the MSM DRM render device can repeat the ioctl to retain references, exhaust kernel memory, and interrupt service.

The record

CVE
CVE-2021-47530
Published
May 24, 2024
Updated
May 11, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
T1499.004
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. May 24, 2024CVE publishedPublication date reported by the CVE source.
  2. May 11, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=5.15
  2. Affected versionversion=a61acbbe9cf873f869fc634ae6f72f214f5994cc <4c3cdbf2540319ea674f1f3c54f31f14c6f39647
  3. Affected versionversion=a61acbbe9cf873f869fc634ae6f72f214f5994cc <ea0006d390a28012f8187717aea61498b2b341e5

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=5.15; version=a61acbbe9cf873f869fc634ae6f72f214f5994cc <4c3cdbf2540319ea674f1f3c54f31f14c6f39647; version=a61acbbe9cf873f869fc634ae6f72f214f5994cc <ea0006d390a28012f8187717aea61498b2b341e5

Published CVSS scores

5.5NIST NVDCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

T1499.004Application or System Exploitation

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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