CVE-2024-36109Public exploitNetwork attack vector

Stored XSS via whitelisted Markdown script tags

Published May 28, 2024 · Updated Aug 2, 2024

Stored cross-site scripting in CoCalc before 419862a9c9879c allows remote authenticated users to execute script through published Markdown. The share server's getXSSOptions sanitizer whitelists script tags in html-ssr.tsx, so attacker-supplied tags survive server-side rendering. A signed-in user must publish the file and another user must view it, exposing data and actions available in the viewer's CoCalc session.

CVSS severity7.6
High
EPSS probability0.41%
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 CoCalc before 419862a9c9879c allows remote authenticated users to execute script through published Markdown. The share server's getXSSOptions sanitizer whitelists script tags in html-ssr.tsx, so attacker-supplied tags survive server-side rendering. A signed-in user must publish the file and another user must view it, exposing data and actions available in the viewer's CoCalc session.

The record

CVE
CVE-2024-36109
Published
May 28, 2024
Updated
Aug 2, 2024
Vendor
SageMath, Inc.
Product
CoCalc
Classifications
CWE-80, CWE-79, T1189
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. May 28, 2024CVE publishedPublication date reported by the CVE source.
  2. Aug 2, 2024Record 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=0 <419862a9c9879c
  2. Affected versionversion=< 419862a9c9879c

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

SageMath, Inc. · CoCalcversion=0 <419862a9c9879c; version=< 419862a9c9879c

Published CVSS scores

7.6GitHub CNACVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:H/I:H/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 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-80Improper Neutralization of Script-Related HTML Tags in a Web Page (Basic XSS)
CWE-79Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
T1189Drive-by Compromise

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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