CVE-2021-3619Network attack vector

Stored XSS via notebook MIME sniffing

Published Aug 17, 2021 · Updated Sep 17, 2024

Stored XSS in Rapid7 Velociraptor 0.5.9 and earlier allows remote authenticated users to run script through a malicious notebook upload. Notebook and download handlers use Go's http.FileServer, which sniffs an uploaded file's MIME type and serves executable content instead of forcing a download. An authenticated Velociraptor account and later viewing of the uploaded notebook content are required, bounding the impact to browser-context data access and actions.

CVSS severity3.5
Low
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 XSS in Rapid7 Velociraptor 0.5.9 and earlier allows remote authenticated users to run script through a malicious notebook upload. Notebook and download handlers use Go's http.FileServer, which sniffs an uploaded file's MIME type and serves executable content instead of forcing a download. An authenticated Velociraptor account and later viewing of the uploaded notebook content are required, bounding the impact to browser-context data access and actions.

The record

CVE
CVE-2021-3619
Published
Aug 17, 2021
Updated
Sep 17, 2024
Vendor
Rapid7
Product
Velociraptor
Classifications
CWE-79, T1059.007
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Aug 17, 2021CVE publishedPublication date reported by the CVE source.
  2. Sep 17, 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=0.5.9 <=0.5.9

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Rapid7 · Velociraptorversion=0.5.9 <=0.5.9

Published CVSS scores

4.8NIST NVDCVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:C/C:L/I:L/A:N
3.5NIST NVDAV:N/AC:M/Au:S/C:N/I:P/A:N
3.5Rapid7CVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:U/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')
T1059.007Command and Scripting Interpreter: JavaScript/JScript

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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