CVE-2021-47292

Service interruption via concurrent io_uring hash-map leak

Published May 21, 2024 · Updated May 11, 2026

Memory leak in Linux kernel 5.12 through 5.13.5 allows local users to interrupt service by racing parallel io_uring_enter calls. In fs/io_uring.c, io_init_wq_offload allocates a hash map without serializing concurrent task-context initialization, so competing assignments overwrite one pointer and leave its allocation unreachable. Triggering the flaw requires low-privileged local syscall access and concurrent calls; repeated races consume kernel memory without affecting confidentiality or integrity.

CVSS severity5.5
Medium
EPSS probability0.19%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Memory leak in Linux kernel 5.12 through 5.13.5 allows local users to interrupt service by racing parallel io_uring_enter calls. In fs/io_uring.c, io_init_wq_offload allocates a hash map without serializing concurrent task-context initialization, so competing assignments overwrite one pointer and leave its allocation unreachable. Triggering the flaw requires low-privileged local syscall access and concurrent calls; repeated races consume kernel memory without affecting confidentiality or integrity.

The record

CVE
CVE-2021-47292
Published
May 21, 2024
Updated
May 11, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
CWE-401, T1499.004
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. May 21, 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=5.12
  2. Affected versionversion=e941894eae31b52f0fd9bdb3ce20620afa152f45 <362a9e65289284f36403058eea2462d0330c1f24
  3. Affected versionversion=e941894eae31b52f0fd9bdb3ce20620afa152f45 <502731a03f27cba1513fbbff77e508185ffce5bb

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=5.12; version=e941894eae31b52f0fd9bdb3ce20620afa152f45 <362a9e65289284f36403058eea2462d0330c1f24; version=e941894eae31b52f0fd9bdb3ce20620afa152f45 <502731a03f27cba1513fbbff77e508185ffce5bb

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

CWE-401Missing Release of Memory after Effective Lifetime
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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