CVE-2021-47328Network attack vector

Kernel compromise via iSCSI connection teardown race

Published May 21, 2024 · Updated Aug 5, 2026

Use-after-free in Linux kernel iSCSI initiator code allows remote attackers controlling a target session to compromise the kernel. During reset cleanup, iscsi_conn_teardown can wake error-handling threads and free iscsi_conn before those threads finish accessing its ehwait field. An established iSCSI session with in-flight I/O and target-driven failures is required; exploitation can disclose or corrupt kernel memory, execute code, or panic the host.

CVSS severity7.8
High
EPSS probability0.76%
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 kernel iSCSI initiator code allows remote attackers controlling a target session to compromise the kernel. During reset cleanup, iscsi_conn_teardown can wake error-handling threads and free iscsi_conn before those threads finish accessing its ehwait field. An established iSCSI session with in-flight I/O and target-driven failures is required; exploitation can disclose or corrupt kernel memory, execute code, or panic the host.

The record

CVE
CVE-2021-47328
Published
May 21, 2024
Updated
Aug 5, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
CWE-416, T1203
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. May 21, 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

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=0adcec66bce9b7e84847da09ae3f8bc36e753312
  2. Affected versionversion=20b38ab5b687df3dbb873cfb0efa946a021f890a
  3. Affected versionversion=3.18.22 <3.19
  4. Affected versionversion=3.2.72 <3.3
  5. Affected versionversion=3.4.111 <3.5
  6. Affected versionversion=4.1.7 <4.2
  7. Affected versionversion=4.2
  8. Affected versionversion=660d0831d1494a6837b2f810d08b5be092c1f31d <89812e7957ab0746eab66ed6fc49d52bb4dca250
  9. Affected versionversion=660d0831d1494a6837b2f810d08b5be092c1f31d <bf20d85a88384574fabb3d53ad62a8af57e7ab11
  10. Affected versionversion=660d0831d1494a6837b2f810d08b5be092c1f31d <d04958a348e560938410e04a12fb99da9c7e6a00
  11. Affected versionversion=660d0831d1494a6837b2f810d08b5be092c1f31d <ec29d0ac29be366450a7faffbcf8cba3a6a3b506
  12. Affected versionversion=660d0831d1494a6837b2f810d08b5be092c1f31d <f0a031f7c55ffd944fead1ddaf2aa94df9a158c1
  13. Affected versionversion=660d0831d1494a6837b2f810d08b5be092c1f31d <fa9542b35ceb4202e8f8d65f440529a63524dca9
  14. Affected versionversion=71b6a23ea944c6a30958bd15a69211e1fd521e1e
  15. Affected versionversion=861a9633c22ee8b484e1b4054995f7e1b94a3834

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=0adcec66bce9b7e84847da09ae3f8bc36e753312; version=20b38ab5b687df3dbb873cfb0efa946a021f890a; version=3.18.22 <3.19; version=3.2.72 <3.3; version=3.4.111 <3.5; version=4.1.7 <4.2; version=4.2; version=660d0831d1494a6837b2f810d08b5be092c1f31d <89812e7957ab0746eab66ed6fc49d52bb4dca250; version=660d0831d1494a6837b2f810d08b5be092c1f31d <bf20d85a88384574fabb3d53ad62a8af57e7ab11; version=660d0831d1494a6837b2f810d08b5be092c1f31d <d04958a348e560938410e04a12fb99da9c7e6a00; version=660d0831d1494a6837b2f810d08b5be092c1f31d <ec29d0ac29be366450a7faffbcf8cba3a6a3b506; version=660d0831d1494a6837b2f810d08b5be092c1f31d <f0a031f7c55ffd944fead1ddaf2aa94df9a158c1; version=660d0831d1494a6837b2f810d08b5be092c1f31d <fa9542b35ceb4202e8f8d65f440529a63524dca9; version=71b6a23ea944c6a30958bd15a69211e1fd521e1e; version=861a9633c22ee8b484e1b4054995f7e1b94a3834

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.

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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)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-416Use After Free
T1203Exploitation for Client Execution

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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