CVE-2021-45457Public exploitNetwork attack vector

Credentialed requests via reflected Origin

Published Jan 6, 2022 · Updated Aug 4, 2024

CORS misconfiguration in Apache Kylin 2.6.6 and earlier, 3.1.2 and earlier, and 4.0.0 lets remote attackers send credentialed cross-origin requests. The CORS filter reflects any supplied Origin and enables Access-Control-Allow-Credentials, so a browser can attach a logged-in user’s cookies or authorization context. Exploitation requires a Kylin user to visit attacker-controlled web content, and can expose or alter operations available to that account.

CVSS severity7.5
High
EPSS probability2.38%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

CORS misconfiguration in Apache Kylin 2.6.6 and earlier, 3.1.2 and earlier, and 4.0.0 lets remote attackers send credentialed cross-origin requests. The CORS filter reflects any supplied Origin and enables Access-Control-Allow-Credentials, so a browser can attach a logged-in user’s cookies or authorization context. Exploitation requires a Kylin user to visit attacker-controlled web content, and can expose or alter operations available to that account.

The record

CVE
CVE-2021-45457
Published
Jan 6, 2022
Updated
Aug 4, 2024
Vendor
The Apache Software Foundation
Product
Apache Kylin
Classifications
CWE-863, T1189
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jan 6, 2022CVE 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=Apache Kylin 2 <=2.6.6
  2. Affected versionversion=Apache Kylin 3 <=3.1.2
  3. Affected versionversion=Apache Kylin 4 <=4.0.0

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

The Apache Software Foundation · Apache Kylinversion=Apache Kylin 2 <=2.6.6; version=Apache Kylin 3 <=3.1.2; version=Apache Kylin 4 <=4.0.0

Published CVSS scores

7.5NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
5.0NVDAV:N/AC:L/Au:N/C:P/I:N/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.

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
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-863Improper Authorization
T1189Drive-by Compromise

Public exploit references

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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