CVE-2021-47548

Out-of-bounds access via improper port bounds

Published May 24, 2024 · Updated May 11, 2026

Improper array-index validation in affected Linux kernels allows local users with CAP_NET_ADMIN to access memory out of bounds during HNS MAC reset. hns_dsaf_ge_srst_by_port() accepts port values below DSAF_GE_NUM (8), then indexes mac_cb, which has only DSAF_MAX_PORT_NUM (6) entries. Reachability requires CAP_NET_ADMIN in the initial user namespace and a real HiSilicon HNS interface; published sources establish no consequence beyond the out-of-bounds access.

CVSS severity9.8
Critical
EPSS probability1.36%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
Coverage for this vulnerability

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Summary

What happened

Improper array-index validation in affected Linux kernels allows local users with CAP_NET_ADMIN to access memory out of bounds during HNS MAC reset. hns_dsaf_ge_srst_by_port() accepts port values below DSAF_GE_NUM (8), then indexes mac_cb, which has only DSAF_MAX_PORT_NUM (6) entries. Reachability requires CAP_NET_ADMIN in the initial user namespace and a real HiSilicon HNS interface; published sources establish no consequence beyond the out-of-bounds access.

The record

CVE
CVE-2021-47548
Published
May 24, 2024
Updated
May 11, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
CWE-129
Attack vector
local
Privileges
admin

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=4.7
  2. Affected versionversion=850bfa3b78ea8849fef78ed74f5f2ccf947db0ca <22519eff7df2d88adcc2568d86046ce1e2b52803
  3. Affected versionversion=850bfa3b78ea8849fef78ed74f5f2ccf947db0ca <948968f8747650447c8f21c9fdba0e1973be040b
  4. Affected versionversion=850bfa3b78ea8849fef78ed74f5f2ccf947db0ca <99bb25cb6753beaf2c2bc37927c2ecc0ceff3f6d
  5. Affected versionversion=850bfa3b78ea8849fef78ed74f5f2ccf947db0ca <a66998e0fbf213d47d02813b9679426129d0d114
  6. Affected versionversion=850bfa3b78ea8849fef78ed74f5f2ccf947db0ca <abbd5faa0748d0aa95d5191d56ff7a17a6275bd1
  7. Affected versionversion=850bfa3b78ea8849fef78ed74f5f2ccf947db0ca <dd07f8971b81ad98cc754b179b331b57f35aa1ff
  8. Affected versionversion=850bfa3b78ea8849fef78ed74f5f2ccf947db0ca <fc7ffa7f10b9454a86369405d9814bf141b30627

What conditions does exploitation require?

Attack vectorlocal
Required privilegesadmin

What is affected?

The Linux Kernel Organization · Linuxversion=4.7; version=850bfa3b78ea8849fef78ed74f5f2ccf947db0ca <22519eff7df2d88adcc2568d86046ce1e2b52803; version=850bfa3b78ea8849fef78ed74f5f2ccf947db0ca <948968f8747650447c8f21c9fdba0e1973be040b; version=850bfa3b78ea8849fef78ed74f5f2ccf947db0ca <99bb25cb6753beaf2c2bc37927c2ecc0ceff3f6d; version=850bfa3b78ea8849fef78ed74f5f2ccf947db0ca <a66998e0fbf213d47d02813b9679426129d0d114; version=850bfa3b78ea8849fef78ed74f5f2ccf947db0ca <abbd5faa0748d0aa95d5191d56ff7a17a6275bd1; version=850bfa3b78ea8849fef78ed74f5f2ccf947db0ca <dd07f8971b81ad98cc754b179b331b57f35aa1ff; version=850bfa3b78ea8849fef78ed74f5f2ccf947db0ca <fc7ffa7f10b9454a86369405d9814bf141b30627
The Linux Kernel Organization · Linux Kernelversion=1da177e4c3f4 <22519eff7df2; version=1da177e4c3f4 <948968f87476; version=1da177e4c3f4 <99bb25cb6753; version=1da177e4c3f4 <a66998e0fbf2; version=1da177e4c3f4 <abbd5faa0748; version=1da177e4c3f4 <dd07f8971b81; version=1da177e4c3f4 <fc7ffa7f10b9

Published CVSS scores

9.8UbuntuCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
9.8CISA ADP VulnrichmentCVSS:3.1/AV:N/AC:L/PR:N/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.

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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
Privilegesadmin
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-129Improper Validation of Array Index

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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