CVE-2022-23656Network attack vector

Stored script execution via unescaped tooltip names

Published Mar 2, 2022 · Updated Apr 23, 2025

Stored cross-site scripting in Zulip Server main builds from 2021-06-03 through 2022-02-28 allows remote authenticated users to run JavaScript. The recent-topics formatter joins participant full names into other_sender_names HTML without escaping them, while Tippy renders the tooltip content as HTML. An attacker needs an account and messages in a multi-participant topic, and execution occurs only when another user opens the overflow tooltip.

CVSS severity4.6
Medium
EPSS probability0.58%
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 main builds from 2021-06-03 through 2022-02-28 allows remote authenticated users to run JavaScript. The recent-topics formatter joins participant full names into other_sender_names HTML without escaping them, while Tippy renders the tooltip content as HTML. An attacker needs an account and messages in a multi-participant topic, and execution occurs only when another user opens the overflow tooltip.

The record

CVE
CVE-2022-23656
Published
Mar 2, 2022
Updated
Apr 23, 2025
Vendor
Zulip
Product
Zulip
Classifications
CWE-79, T1203
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Mar 2, 2022CVE publishedPublication date reported by the CVE source.
  2. Apr 23, 2025Record 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=>= 2021-06-03, < 2022-03-01

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Zulip · Zulipversion=>= 2021-06-03, < 2022-03-01

Published CVSS scores

4.6GitHub, Inc.CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:L/I:L/A:N
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 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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