CVE-2021-47589

Kernel use-after-free via stale NAPI entry

Published Jun 19, 2024 · Updated May 11, 2026

Use-after-free in Linux igbvf probing allows local users to cause unsafe kernel memory access when network-device registration fails. The error path frees adapter->rx_ring before free_netdev traverses dev->napi_list and removes the ring's still-linked NAPI entry. Reachability requires an Intel 82576 virtual-function device, SR-IOV support, and a register_netdev failure; the record demonstrates a KASAN-detected read but not code execution or data disclosure.

CVSS severity7.8
High
EPSS probability0.26%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Use-after-free in Linux igbvf probing allows local users to cause unsafe kernel memory access when network-device registration fails. The error path frees adapter->rx_ring before free_netdev traverses dev->napi_list and removes the ring's still-linked NAPI entry. Reachability requires an Intel 82576 virtual-function device, SR-IOV support, and a register_netdev failure; the record demonstrates a KASAN-detected read but not code execution or data disclosure.

The record

CVE
CVE-2021-47589
Published
Jun 19, 2024
Updated
May 11, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
CWE-415
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Jun 19, 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=2.6.30
  2. Affected versionversion=d4e0fe01a38a073568aee541a0247fe734095979 <74a16e062b23332d8db017ff4a41e16279c44411
  3. Affected versionversion=d4e0fe01a38a073568aee541a0247fe734095979 <79d9b092035dcdbe636b70433149df9cc6db1e49
  4. Affected versionversion=d4e0fe01a38a073568aee541a0247fe734095979 <8addba6cab94ce01686ea2e80ed1530f9dc33a9a
  5. Affected versionversion=d4e0fe01a38a073568aee541a0247fe734095979 <8d0c927a9fb2b4065230936b77b54f857a3754fc
  6. Affected versionversion=d4e0fe01a38a073568aee541a0247fe734095979 <944b8be08131f5faf2cd2440aa1c24a39a163a54
  7. Affected versionversion=d4e0fe01a38a073568aee541a0247fe734095979 <b6d335a60dc624c0d279333b22c737faa765b028
  8. Affected versionversion=d4e0fe01a38a073568aee541a0247fe734095979 <cc9b655bb84f1be283293dfea94dff9a31b106ac
  9. Affected versionversion=d4e0fe01a38a073568aee541a0247fe734095979 <ffe1695b678729edec04037e691007900a2b2beb

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=2.6.30; version=d4e0fe01a38a073568aee541a0247fe734095979 <74a16e062b23332d8db017ff4a41e16279c44411; version=d4e0fe01a38a073568aee541a0247fe734095979 <79d9b092035dcdbe636b70433149df9cc6db1e49; version=d4e0fe01a38a073568aee541a0247fe734095979 <8addba6cab94ce01686ea2e80ed1530f9dc33a9a; version=d4e0fe01a38a073568aee541a0247fe734095979 <8d0c927a9fb2b4065230936b77b54f857a3754fc; version=d4e0fe01a38a073568aee541a0247fe734095979 <944b8be08131f5faf2cd2440aa1c24a39a163a54; version=d4e0fe01a38a073568aee541a0247fe734095979 <b6d335a60dc624c0d279333b22c737faa765b028; version=d4e0fe01a38a073568aee541a0247fe734095979 <cc9b655bb84f1be283293dfea94dff9a31b106ac; version=d4e0fe01a38a073568aee541a0247fe734095979 <ffe1695b678729edec04037e691007900a2b2beb

Published CVSS scores

7.8NIST NVDCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
5.5Amazon LinuxCVSS: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-415Double Free

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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