CVE-2023-33186Network attack vector

JavaScript execution via unsanitized topic tooltip

Published May 30, 2023 · Updated Jan 10, 2025

Stored cross-site scripting in Zulip Server 7.0-beta1 through 7.0-beta2 allows remote authenticated users to execute JavaScript. The message-feed tooltip handler concatenates an attacker-controlled topic from data-tippy-content with hotkey-hint HTML and passes the combined string to parse_html(), creating executable DOM content. The attacker must be able to send a crafted-topic message, and execution requires a recipient to hover over that topic's tooltip.

CVSS severity8.2
High
EPSS probability0.62%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Stored cross-site scripting in Zulip Server 7.0-beta1 through 7.0-beta2 allows remote authenticated users to execute JavaScript. The message-feed tooltip handler concatenates an attacker-controlled topic from data-tippy-content with hotkey-hint HTML and passes the combined string to parse_html(), creating executable DOM content. The attacker must be able to send a crafted-topic message, and execution requires a recipient to hover over that topic's tooltip.

The record

CVE
CVE-2023-33186
Published
May 30, 2023
Updated
Jan 10, 2025
Vendor
Zulip
Product
Zulip
Classifications
CWE-79, T1203
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. May 30, 2023CVE publishedPublication date reported by the CVE source.
  2. Jan 10, 2025Record 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?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=>= 7.0-beta1, < 7.0-beta3

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Zulip · Zulipversion=>= 7.0-beta1, < 7.0-beta3

Published CVSS scores

6.1NISTCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
8.2GitHub, Inc.CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:L/A:L

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
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

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

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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