How severe is CVE-2021-32660?

CVE-2021-32660 has a CVSS score of 8.1/10, rated HIGH. Immediate patching is strongly recommended.

Which packages are affected by CVE-2021-32660?

CVE-2021-32660 affects the following packages: @backstage/techdocs-common (npm). Ecosystems affected: npm.

How do I fix CVE-2021-32660?

Update @backstage/techdocs-common to 0.6.4 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2021-32660 is resolved across your whole dependency graph.

How do I detect CVE-2021-32660 in my npm dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for @backstage/techdocs-common, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

How do I mitigate CVE-2021-32660 if there is no patch (or I can't update yet)?

Stop passing untrusted input into the interpreter or shell: call the affected binary with an argument array rather than a composed command string, reject anything outside a strict allowlist of expected values, and run the component under an account that cannot reach beyond the work it legitimately does.

Is CVE-2021-32660 actively exploited in the wild?

No public exploit code has been indexed for CVE-2021-32660 yet. This does not mean the vulnerability cannot be exploited — absence of public exploits does not imply safety. Apply the recommended fix and use O3 Security to monitor your exposure.

What is the EPSS score for CVE-2021-32660?

CVE-2021-32660 has an EPSS (Exploit Prediction Scoring System) score of 1.3%, placing it in the 70th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. This score indicates relatively lower exploitation probability, though the CVSS severity should still guide your patching priority.

What type of vulnerability is CVE-2021-32660?

CVE-2021-32660 is classified as CWE-77 (CWE-77), Unrestricted File Upload (CWE-434). These weakness types describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation.

When was CVE-2021-32660 published, and has it been updated?

CVE-2021-32660 was published on June 3, 2021 and was last updated on October 20, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

📦

📦 npm

Not in CISA KEV

HIGH severity

CVE-2021-32660 — @backstage/techdocs-common

HIGHFix: backstage/backstage@aad98c5

CVE-2021-32660 is a high-severity (CVSS 8.1) CWE-77 vulnerability in @backstage/techdocs-common. A fix is available for @backstage/techdocs-common — see the affected versions and patch details below.

Script injection

Also known asGHSA-pwhf-39xg-4rxw

Published

Jun 3, 2021

Updated

Oct 20, 2026

Affected

1 pkg

Patched

1 / 1

Exploits

None indexed

Exploitation data as of Oct 30, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

EPSS Exploitation Probability

via FIRST.org ↗

1.3%probability of exploitation in next 30 days

Lower Risk0.00%

Lower risk than most CVEs70th percentile — riskier than 70% of all scored CVEsHighest risk

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

How urgent is this, really

Where this sits among everything scored

Real-World Exposure

1 pkg affected

How broadly this vulnerability is actually deployed: weekly install volume shows current usage, and reverse-dependency count shows how many other packages break if it stays unpatched.

0other npm packages depend on this — each one inherits the vulnerability until it's patched upstream

@backstage/techdocs-commonnpm

1Kdownloads / week

Description

Impact

A malicious internal actor is able to upload documentation content with malicious scripts. These scripts would normally be sanitized by the TechDocs frontend, but by tricking a user to visit the content via the TechDocs API, the content sanitazion will be bypassed. If the TechDocs API is hosted on the same origin as the Backstage app or other backend plugins, this may give access to sensitive data.

The ability to upload malicious content may be limited by internal code review processes, unless the chosen TechDocs deployment method is to use an object store and the actor has access to upload files directly to that store.

Patches

The vulnerability is patched in the 0.6.4 release of @backstage/techdocs-common.

For more information

If you have any questions or comments about this advisory:

Open an issue in the Backstage repository
Visit our chat, linked to in Backstage README

Affected Packages

1 total 1 fixed

Ecosystem	Package	Vulnerable range	Fix
📦npm	`@backstage/techdocs-common`	all versions	0.6.4`npm install @backstage/techdocs-common@0.6.4`

Affected Products

1 product · 1 configurations

Application

\@backstage\/techdocs-commonlinuxfoundation

< 0.6.4

range

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for @backstage/techdocs-common, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update @backstage/techdocs-common to 0.6.4 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2021-32660 is resolved across your whole dependency graph.
Workarounds
Stop passing untrusted input into the interpreter or shell: call the affected binary with an argument array rather than a composed command string, reject anything outside a strict allowlist of expected values, and run the component under an account that cannot reach beyond the work it legitimately does.

Frequently Asked Questions

### Impact A malicious internal actor is able to upload documentation content with malicious scripts. These scripts would normally be sanitized by the TechDocs frontend, but by tricking a user to visit the content via the TechDocs API, the content sanitazion will be bypassed. If the TechDocs API is hosted on the same origin as the Backstage app or other backend plugins, this may give access to sensitive data. The ability to upload malicious content may be limited by internal code review processes, unless the chosen TechDocs deployment method is to use an object store and the actor has access

O3 Security · Impact-Aware SCA

Is CVE-2021-32660 in your dependencies?

Find it across npm, including transitive dependencies.

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CVSS Score

8.1/10CVSS v3 base

Vector breakdown

Attack Vector

Network

Attack Complexity

Low

Privileges Required

None

User Interaction

Required

Scope

Unchanged

Confidentiality

High

Integrity

High

Availability

None

Raw vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:N

CWE Classification

CWE-77CWE-77 CWE-434Unrestricted File Upload

Weaponization

No Nuclei template, Metasploit module or public proof-of-concept found.

OpenSSF Scorecard

Package health score

backstage

6.2/10

Code-Review10/10

Dependency-Update-Tool10/10

Maintained10/10

Vulnerabilities0/10

Branch-Protection8/10

Assessed Oct 30, 2026

Timeline

Disclosed

Jun 3, 2021

Last updated

Oct 20, 2026

Identifiers

CVE-2021-32660

GHSA-pwhf-39xg-4rxw

References

Advisorygithub.com · GHSA pwhf 39xg 4rxw Advisorynvd.nist.gov · CVE 2021 32660 Fixgithub.com · aad98c544e59369901fe9e0a85f6357644dceb5c Fixgithub.com · release 2021 06 03

Related vulnerabilities

Also affects @backstage/techdocs-common

This CVE is high severity — higher than any of the other 2 CVEs affecting @backstage/techdocs-common (highest there: moderate).

GHSA-4jqc-jvh2-pxg9CVE-2021-32662

Same weakness: CWE-77

This CVE is high severity; 6 of 6 other CVEs with CWE-77 are rated as high or higher (top: critical).

CVE-2026-106765CVE-2026-106764CVE-2026-112942CVE-2026-102827CVE-2026-102826GHSA-jqmf-mx4f-hfr6Browse all CWE-77

Provenance

Sources

OSV.devNVDFIRST.org (EPSS)

Last verifiedOct 20, 2026