CVE-2021-47246

Device-removal disruption via unreleased hairpin send queue

Published May 21, 2024 · Updated May 11, 2026

Resource leak in the mlx5e hairpin-flow code in Linux allows local users to disrupt PCI device removal by unbinding a peer device. When a peer net device is removed before its hairpin flow, the code leaves the firmware send queue alive, retaining its host-memory ring pages. Local privileges and mlx5 hardware with a configured hairpin flow are required; subsequent PCI removal times out while reclaiming pages and leaks a command resource.

CVSS severity5.5
Medium
EPSS probability0.22%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Resource leak in the mlx5e hairpin-flow code in Linux allows local users to disrupt PCI device removal by unbinding a peer device. When a peer net device is removed before its hairpin flow, the code leaves the firmware send queue alive, retaining its host-memory ring pages. Local privileges and mlx5 hardware with a configured hairpin flow are required; subsequent PCI removal times out while reclaiming pages and leaks a command resource.

The record

CVE
CVE-2021-47246
Published
May 21, 2024
Updated
May 11, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
CWE-401, T1499
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=4.19
  2. Affected versionversion=4d8fcf216c90bc25e34ae2200aa8985ee3158898 <4b16118665e94c90a3e84a5190486fd0e4eedd74
  3. Affected versionversion=4d8fcf216c90bc25e34ae2200aa8985ee3158898 <a3e5fd9314dfc4314a9567cde96e1aef83a7458a
  4. Affected versionversion=4d8fcf216c90bc25e34ae2200aa8985ee3158898 <b374c1304f6d3d4752ad1412427b7bf02bb1fd61
  5. Affected versionversion=4d8fcf216c90bc25e34ae2200aa8985ee3158898 <be7f3f401d224e1efe8112b2fa8b837eeb8c5e52

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=4.19; version=4d8fcf216c90bc25e34ae2200aa8985ee3158898 <4b16118665e94c90a3e84a5190486fd0e4eedd74; version=4d8fcf216c90bc25e34ae2200aa8985ee3158898 <a3e5fd9314dfc4314a9567cde96e1aef83a7458a; version=4d8fcf216c90bc25e34ae2200aa8985ee3158898 <b374c1304f6d3d4752ad1412427b7bf02bb1fd61; version=4d8fcf216c90bc25e34ae2200aa8985ee3158898 <be7f3f401d224e1efe8112b2fa8b837eeb8c5e52

Published CVSS scores

5.5NIST National Vulnerability DatabaseCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
3.3SUSECVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L

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
T1499Endpoint Denial of Service

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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