CVE-2021-33489Public exploitNetwork attack vector

Session hijacking via unsanitized XCF media type

Published Nov 22, 2021 · Updated Aug 3, 2024

Cross-site scripting in the OX App Suite backend 7.10.5 and earlier allows remote attackers to execute script through a shared XCF file. The backend sanitization engine fails to recognize the file's media type, so embedded HTML and JavaScript bypass filtering instead of being forced to download. Exploitation requires a victim to follow the file's direct sharing link; the script then runs in that user's web context and can hijack the session or trigger unwanted actions.

CVSS severity5.3
Medium
EPSS probability1.30%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Cross-site scripting in the OX App Suite backend 7.10.5 and earlier allows remote attackers to execute script through a shared XCF file. The backend sanitization engine fails to recognize the file's media type, so embedded HTML and JavaScript bypass filtering instead of being forced to download. Exploitation requires a victim to follow the file's direct sharing link; the script then runs in that user's web context and can hijack the session or trigger unwanted actions.

The record

CVE
CVE-2021-33489
Published
Nov 22, 2021
Updated
Aug 3, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-79, CWE-80, T1204.001
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Nov 22, 2021CVE publishedPublication date reported by the CVE source.
  2. Aug 3, 2024Record 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?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

5.3Open-XchangeCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N
6.1NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
4.3NVDAV:N/AC:M/Au:N/C:N/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.

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 exploitPublished

Weakness, pattern, technique

CWE-79Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
CWE-80Improper Neutralization of Script-Related HTML Tags in a Web Page (Basic XSS)
T1204.001User Execution: Malicious Link

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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