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Fencer Vulns
medium 6.8

CVE-2021-32660 json

TechDocs content sanitization bypass

published 2021-06-03 5 y ago modified 2026-07-08 4 mo ago also GHSA-pwhf-39xg-4rxw , EUVD-2021-1373

cvss
6.8
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
1.3%
EPSS 1.3% chance of exploitation in 30 days, percentile 69%
public exploits
0
none known

Summary

Backstage is an open platform for building developer portals, and techdocs-common contains common functionalities for Backstage's TechDocs. In versions of `@backstage/tehdocs-common` prior to 0.6.4, 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. The vulnerability is patched in the `0.6.4` release of `@backstage/techdocs-common`.

Patch / fix

  • npm @backstage/techdocs-common 0.6.4
  • linuxfoundation @backstage/techdocs-common 0.6.4

Exploit prediction

1.27% chance of exploitation in the next 30 days, higher than 69% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 3.1 6.8 CVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:U/C:H/I:H/A:H
NVD 3.1 8.1 CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:N
NVD 2.0 5.8 AV:N/AC:M/Au:N/C:P/I:P/A:N
GitHub 3.1 6.8 CVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:U/C:H/I:H/A:H

Affected packages

ecosystem package affected fixed in
npm @backstage/techdocs-common
<0.6.4
0.6.4

Affected products

  • backstage backstage

Classification

Weakness
  • CWE-77 Improper Neutralization of Special Elements used in a Command
  • CWE-434 Unrestricted Upload of File with Dangerous Type

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.