CVE-2021-32660Network attack vector

Sensitive data access via unsanitized TechDocs API

Published Jun 3, 2021 · Updated Aug 3, 2024

Stored cross-site scripting in Backstage TechDocs before 0.6.4 allows remote authenticated users to access sensitive same-origin data. The TechDocs API returns attacker-uploaded documentation HTML directly, bypassing the frontend sanitizer that normally strips malicious scripts. Exploitation requires permission to publish documentation or write to its object store, a victim visit to the API content, and same-origin hosting with sensitive services.

CVSS severity6.8
Medium
EPSS probability1.27%
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 Backstage TechDocs before 0.6.4 allows remote authenticated users to access sensitive same-origin data. The TechDocs API returns attacker-uploaded documentation HTML directly, bypassing the frontend sanitizer that normally strips malicious scripts. Exploitation requires permission to publish documentation or write to its object store, a victim visit to the API content, and same-origin hosting with sensitive services.

The record

CVE
CVE-2021-32660
Published
Jun 3, 2021
Updated
Aug 3, 2024
Vendor
Backstage
Product
Backstage
Classifications
CWE-77, CWE-434, T1189
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Jun 3, 2021CVE publishedPublication date reported by the CVE source.
  2. Aug 3, 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=< 0.6.4

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Backstage · Backstageversion=< 0.6.4

Published CVSS scores

6.8GitHub, Inc.CVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:U/C:H/I:H/A:H
5.8NIST NVDAV:N/AC:M/Au:N/C:P/I:P/A:N
8.1NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/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-77Improper Neutralization of Special Elements used in a Command ('Command Injection')
CWE-434Unrestricted Upload of File with Dangerous Type
T1189Drive-by Compromise

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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