CVE-2021-47148

Kernel memory corruption via unchecked RSS context

Published Mar 25, 2024 · Updated Aug 5, 2026

Out-of-bounds write in Linux 5.12 through 5.12.8 allows local users to corrupt kernel memory through an RSS-context ioctl. otx2_set_rxfh_context uses the user-controlled rss_context value to index rss->rss_ctx without checking it against MAX_RSS_GROUPS before writing the indirection table. Reachability requires CAP_NET_ADMIN in the owning network namespace and a Marvell OcteonTX2 PF or VF interface using the affected driver.

CVSS severity7.8
High
EPSS probability0.23%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Out-of-bounds write in Linux 5.12 through 5.12.8 allows local users to corrupt kernel memory through an RSS-context ioctl. otx2_set_rxfh_context uses the user-controlled rss_context value to index rss->rss_ctx without checking it against MAX_RSS_GROUPS before writing the indirection table. Reachability requires CAP_NET_ADMIN in the owning network namespace and a Marvell OcteonTX2 PF or VF interface using the affected driver.

The record

CVE
CVE-2021-47148
Published
Mar 25, 2024
Updated
Aug 5, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
CWE-787
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Mar 25, 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=5.12
  2. Affected versionversion=81a4362016e7d8b17031fe1aa43cdb58a7f0f163 <389146bc6d2bbb20714d06624b74856320ce40f7
  3. Affected versionversion=81a4362016e7d8b17031fe1aa43cdb58a7f0f163 <e5cc361e21648b75f935f9571d4003aaee480214

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=5.12; version=81a4362016e7d8b17031fe1aa43cdb58a7f0f163 <389146bc6d2bbb20714d06624b74856320ce40f7; version=81a4362016e7d8b17031fe1aa43cdb58a7f0f163 <e5cc361e21648b75f935f9571d4003aaee480214

Published CVSS scores

7.8kernel.orgCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
5.5SUSECVSS: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

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No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-787Out-of-bounds Write

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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