CVE-2021-37705Network attack vector

Cross-tenant code execution via unchecked token issuer

Published Aug 13, 2021 · Updated Aug 4, 2024

Improper authorization in Microsoft OneFuzz 2.12.0 through 2.30.0 allows remote authenticated users to execute code via API calls. The API authentication path accepts Azure Active Directory bearer tokens without comparing the issuer claim to an administrator-configured tenant allowlist. Exposure requires the non-default multi-tenant deployment option; any Azure Active Directory tenant account can read or alter private fuzzing data and run code on Azure compute resources.

CVSS severity10.0
Critical
EPSS probability2.42%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Improper authorization in Microsoft OneFuzz 2.12.0 through 2.30.0 allows remote authenticated users to execute code via API calls. The API authentication path accepts Azure Active Directory bearer tokens without comparing the issuer claim to an administrator-configured tenant allowlist. Exposure requires the non-default multi-tenant deployment option; any Azure Active Directory tenant account can read or alter private fuzzing data and run code on Azure compute resources.

The record

CVE
CVE-2021-37705
Published
Aug 13, 2021
Updated
Aug 4, 2024
Vendor
Microsoft
Product
OneFuzz
Classifications
CWE-346, CWE-285, CWE-863, T1078.004
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Aug 13, 2021CVE publishedPublication date reported by the CVE source.
  2. Aug 4, 2024Record 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=>= 2.12.0, < 2.31.0

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Microsoft · OneFuzzversion=>= 2.12.0, < 2.31.0

Published CVSS scores

10.0GitHubCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:L
6.8NIST NVDAV:N/AC:M/Au:N/C:P/I:P/A:P
10.0NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/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 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-346Origin Validation Error
CWE-285Improper Authorization
CWE-863Incorrect Authorization
T1078.004Valid Accounts: Cloud Accounts

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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