CVE-2020-9445Network attack vector

Cross-site scripting via modal_link Markdown rendering

Published Apr 20, 2020 · Updated Aug 4, 2024

Cross-site scripting in Zulip Server before 2.1.3 allows remote attackers to execute script via crafted modal_link Markdown. The vendor identifies the obsolete modal_link Markdown feature as the vulnerable locus but does not disclose the exact unsafe transformation or escaping failure. Exploitation requires a victim to interact with rendered attacker-controlled content and permits script execution in the victim's browser context.

CVSS severity6.1
Medium
EPSS probability0.67%
Next 30 days · Sep 17, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Cross-site scripting in Zulip Server before 2.1.3 allows remote attackers to execute script via crafted modal_link Markdown. The vendor identifies the obsolete modal_link Markdown feature as the vulnerable locus but does not disclose the exact unsafe transformation or escaping failure. Exploitation requires a victim to interact with rendered attacker-controlled content and permits script execution in the victim's browser context.

The record

CVE
CVE-2020-9445
Published
Apr 20, 2020
Updated
Aug 4, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-79, T1203
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Apr 20, 2020CVE 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?

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

4.3NIST NVDAV:N/AC:M/Au:N/C:N/I:P/A:N
6.1NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/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 11, 2026Sep 17, 2026
Latest reporting daySep 17, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
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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