CVE-2021-38575Network attack vector

Initiator compromise via unchecked CHAP decoding

Published Dec 1, 2021 · Updated Nov 3, 2025

Buffer overflow in TianoCore EDK II edk2-stable202105 and earlier allows remote attackers to compromise iSCSI initiators. IScsiHexToBin decodes target-supplied CHAP_C and CHAP_R strings into caller-provided buffers without verifying that the decoded data fits. A malicious iSCSI target can trigger memory corruption during CHAP negotiation, compromising the initiator without privileges or user interaction.

CVSS severity8.1
High
EPSS probability1.85%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Buffer overflow in TianoCore EDK II edk2-stable202105 and earlier allows remote attackers to compromise iSCSI initiators. IScsiHexToBin decodes target-supplied CHAP_C and CHAP_R strings into caller-provided buffers without verifying that the decoded data fits. A malicious iSCSI target can trigger memory corruption during CHAP negotiation, compromising the initiator without privileges or user interaction.

The record

CVE
CVE-2021-38575
Published
Dec 1, 2021
Updated
Nov 3, 2025
Vendor
TianoCore
Product
EDK II
Classifications
CWE-119, CWE-124, T1203
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Dec 1, 2021CVE publishedPublication date reported by the CVE source.
  2. Nov 3, 2025Record 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=unspecified <=edk2-stable202105

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

TianoCore · EDK IIversion=unspecified <=edk2-stable202105

Published CVSS scores

6.8NIST NVDAV:N/AC:M/Au:N/C:P/I:P/A:P
8.1NIST NVDCVSS:3.1/AV:N/AC:H/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.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-119Improper Restriction of Operations within the Bounds of a Memory Buffer
CWE-124Buffer Underwrite ('Buffer Underflow')
T1203Exploitation for Client Execution

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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