CVE-2021-47485

Kernel memory corruption via unchecked SDMA size arithmetic

Published May 22, 2024 · Updated Aug 5, 2026

Buffer overflow in the qib user-SDMA path in affected Linux kernels allows local users to corrupt kernel memory through crafted buffers. qib_user_sdma_queue_pkts accumulates user-controlled lengths into bytes_togo and derives addrlimit and allocation sizes without detecting integer overflow or field truncation. Reachability requires local access to the qib user-SDMA interface; successful corruption can crash the host or alter protected kernel state.

CVSS severity7.8
High
EPSS probability0.24%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Buffer overflow in the qib user-SDMA path in affected Linux kernels allows local users to corrupt kernel memory through crafted buffers. qib_user_sdma_queue_pkts accumulates user-controlled lengths into bytes_togo and derives addrlimit and allocation sizes without detecting integer overflow or field truncation. Reachability requires local access to the qib user-SDMA interface; successful corruption can crash the host or alter protected kernel state.

The record

CVE
CVE-2021-47485
Published
May 22, 2024
Updated
Aug 5, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
CWE-120, T1068
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. May 22, 2024CVE publishedPublication date reported by the CVE source.
  2. Aug 5, 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=2.6.35
  2. Affected versionversion=f931551bafe1f10ded7f5282e2aa162c267a2e5d <0d4395477741608d123dad51def9fe50b7ebe952
  3. Affected versionversion=f931551bafe1f10ded7f5282e2aa162c267a2e5d <0f8cdfff06829a0b0348b6debc29ff6a61967724
  4. Affected versionversion=f931551bafe1f10ded7f5282e2aa162c267a2e5d <3f57c3f67fd93b4da86aeffea1ca32c484d054ad
  5. Affected versionversion=f931551bafe1f10ded7f5282e2aa162c267a2e5d <60833707b968d5ae02a75edb7886dcd4a957cf0d
  6. Affected versionversion=f931551bafe1f10ded7f5282e2aa162c267a2e5d <73d2892148aa4397a885b4f4afcfc5b27a325c42
  7. Affected versionversion=f931551bafe1f10ded7f5282e2aa162c267a2e5d <bda41654b6e0c125a624ca35d6d20beb8015b5d0
  8. Affected versionversion=f931551bafe1f10ded7f5282e2aa162c267a2e5d <c3e17e58f571f34c51aeb17274ed02c2ed5cf780
  9. Affected versionversion=f931551bafe1f10ded7f5282e2aa162c267a2e5d <d39bf40e55e666b5905fdbd46a0dced030ce87be

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=2.6.35; version=f931551bafe1f10ded7f5282e2aa162c267a2e5d <0d4395477741608d123dad51def9fe50b7ebe952; version=f931551bafe1f10ded7f5282e2aa162c267a2e5d <0f8cdfff06829a0b0348b6debc29ff6a61967724; version=f931551bafe1f10ded7f5282e2aa162c267a2e5d <3f57c3f67fd93b4da86aeffea1ca32c484d054ad; version=f931551bafe1f10ded7f5282e2aa162c267a2e5d <60833707b968d5ae02a75edb7886dcd4a957cf0d; version=f931551bafe1f10ded7f5282e2aa162c267a2e5d <73d2892148aa4397a885b4f4afcfc5b27a325c42; version=f931551bafe1f10ded7f5282e2aa162c267a2e5d <bda41654b6e0c125a624ca35d6d20beb8015b5d0; version=f931551bafe1f10ded7f5282e2aa162c267a2e5d <c3e17e58f571f34c51aeb17274ed02c2ed5cf780; version=f931551bafe1f10ded7f5282e2aa162c267a2e5d <d39bf40e55e666b5905fdbd46a0dced030ce87be

Published CVSS scores

7.8NIST NVDCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/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.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

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-120Buffer Copy without Checking Size of Input ('Classic Buffer Overflow')
T1068Exploitation for Privilege Escalation

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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