CVE-2021-33495Public exploitNetwork attack vector

Session hijacking via unescaped system-message DOM insertion

Published Nov 22, 2021 · Updated Aug 3, 2024

Stored XSS in OX Chat in Open-Xchange OX App Suite 7.10.5 allows context-dependent attackers to run script in a participant's session. An OX Chat method inserts system-message content into the DOM without escaping HTML or JavaScript. The attacker must share the victim's OX context, and victims must join and interact with Chat; execution enables session hijacking or unwanted web-interface actions.

CVSS severity5.3
Medium
EPSS probability1.13%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Stored XSS in OX Chat in Open-Xchange OX App Suite 7.10.5 allows context-dependent attackers to run script in a participant's session. An OX Chat method inserts system-message content into the DOM without escaping HTML or JavaScript. The attacker must share the victim's OX context, and victims must join and interact with Chat; execution enables session hijacking or unwanted web-interface actions.

The record

CVE
CVE-2021-33495
Published
Nov 22, 2021
Updated
Aug 3, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-80, T1185
Attack vector
network
Privileges
Unavailable

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

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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 privilegesUnavailable in this record.

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

6.1NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
5.3OX Software GmbHCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N
4.3NIST NVDAV: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 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
PrivilegesUnavailable
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-80Improper Neutralization of Script-Related HTML Tags in a Web Page (Basic XSS)
T1185Browser Session Hijacking

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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