CVE-2021-47057

Local service interruption via DMA mapping leak

Published Feb 29, 2024 · Updated May 11, 2026

Resource exhaustion in affected Linux kernels allows local users to interrupt service via failed sun8i-ss IV DMA mappings. In sun8i_ss_prng_generate, the IV mapping-error branch returns after kzalloc allocates buffer d but before kfree releases it. A local user must reach the hardware-backed PRNG on an Allwinner A80/A83T system; repeated failures consume kernel memory and affect availability only.

CVSS severity5.5
Medium
EPSS probability0.22%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Resource exhaustion in affected Linux kernels allows local users to interrupt service via failed sun8i-ss IV DMA mappings. In sun8i_ss_prng_generate, the IV mapping-error branch returns after kzalloc allocates buffer d but before kfree releases it. A local user must reach the hardware-backed PRNG on an Allwinner A80/A83T system; repeated failures consume kernel memory and affect availability only.

The record

CVE
CVE-2021-47057
Published
Feb 29, 2024
Updated
May 11, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
CWE-770, T1499
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Feb 29, 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=5.10
  2. Affected versionversion=ac2614d721dea2ff273af19c6c5d508d58a2bb3e <617ec35ed51f731a593ae7274228ef2cfc9cb781
  3. Affected versionversion=ac2614d721dea2ff273af19c6c5d508d58a2bb3e <6516cb852d704ff8d615de1f93cd443a99736c3d
  4. Affected versionversion=ac2614d721dea2ff273af19c6c5d508d58a2bb3e <98b5ef3e97b16eaeeedb936f8bda3594ff84a70e
  5. Affected versionversion=ac2614d721dea2ff273af19c6c5d508d58a2bb3e <e1f2d739849c3239df1ea3f97d40bade4b808410

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=5.10; version=ac2614d721dea2ff273af19c6c5d508d58a2bb3e <617ec35ed51f731a593ae7274228ef2cfc9cb781; version=ac2614d721dea2ff273af19c6c5d508d58a2bb3e <6516cb852d704ff8d615de1f93cd443a99736c3d; version=ac2614d721dea2ff273af19c6c5d508d58a2bb3e <98b5ef3e97b16eaeeedb936f8bda3594ff84a70e; version=ac2614d721dea2ff273af19c6c5d508d58a2bb3e <e1f2d739849c3239df1ea3f97d40bade4b808410

Published CVSS scores

5.5CISA-ADPCVSS: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

CWE-770Allocation of Resources Without Limits or Throttling
T1499Endpoint Denial of Service

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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