CVE-2020-8288Public exploitNetwork attack vector

Stored XSS via unneutralized rendering value

Published Jan 21, 2021 · Updated Aug 4, 2024

Stored XSS in Rocket.Chat Server before 3.9.2 allows remote authenticated users to run script in another user's browser via a message. The specializedRendering function processes the value parameter as rendered message content without neutralizing executable markup. Exploitation requires crafted content and another user to render it, enabling privilege elevation or message modification in that user's session.

CVSS severity5.4
Medium
EPSS probability0.85%
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 Rocket.Chat Server before 3.9.2 allows remote authenticated users to run script in another user's browser via a message. The specializedRendering function processes the value parameter as rendered message content without neutralizing executable markup. Exploitation requires crafted content and another user to render it, enabling privilege elevation or message modification in that user's session.

The record

CVE
CVE-2020-8288
Published
Jan 21, 2021
Updated
Aug 4, 2024
Vendor
Rocket.Chat
Product
Rocket.Chat Server
Classifications
CWE-79, T1203
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Jan 21, 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=Fixed in 3.9.2

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Rocket.Chat · Rocket.Chat Serverversion=Fixed in 3.9.2

Published CVSS scores

3.5NIST NVDAV:N/AC:M/Au:S/C:N/I:P/A:N
5.4NIST NVDCVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/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
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-79Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
T1203Exploitation for Client Execution

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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