CVE-2021-38621Network attack vector

Cross-user file deletion via missing ownership check

Published Aug 13, 2021 · Updated Aug 4, 2024

Improper authorization in Agora Flat Server before 2021-07-30 allows remote authenticated users to delete other users' cloud files. The AlibabaCloudRemoveFile controller accepted caller-supplied file UUIDs without verifying that each CloudStorageUserFiles record belonged to the current user. Access to an authenticated account and knowledge of another file UUID are required; successful exploitation deletes that file from Alibaba Cloud storage.

CVSS severity9.1
Critical
EPSS probability0.99%
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 Agora Flat Server before 2021-07-30 allows remote authenticated users to delete other users' cloud files. The AlibabaCloudRemoveFile controller accepted caller-supplied file UUIDs without verifying that each CloudStorageUserFiles record belonged to the current user. Access to an authenticated account and knowledge of another file UUID are required; successful exploitation deletes that file from Alibaba Cloud storage.

The record

CVE
CVE-2021-38621
Published
Aug 13, 2021
Updated
Aug 4, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
T1485
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?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

9.1NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
6.4NIST NVDAV:N/AC:L/Au:N/C:P/I:P/A:N

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)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

T1485Data Destruction

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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