No exploitation reportedFix available

CVE-2021-41151

Q: Is CVE-2021-41151 actively exploited?

Active exploitation of CVE-2021-41151 has not been confirmed. Its EPSS score was 1.3% on 2026-10-23, the estimated probability of exploitation in the next 30 days.

Q: What is the CVSS score for CVE-2021-41151?

CVE-2021-41151 has a CVSS v3 base score of 4.9 (MEDIUM severity), with vector string CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:N/A:N.

No exploitation reported by the sources we read.

Published2021-10-18
Fixed in0.15.9
WeaknessCWE-22

Am I affected?

With a domain, we read the version its public headers and pages expose. A distribution build can carry the fix under an older number.

Description

Backstage is an open platform for building developer portals. In affected versions A malicious actor could read sensitive files from the environment where Scaffolder Tasks are run. The attack is executed by crafting a custom Scaffolder template with a `github:publish:pull-request` action and a particular source path. When the template is executed the sensitive files would be included in the published pull request. This vulnerability is mitigated by the fact that an attacker would need access to create and register templates in the Backstage catalog, and that the attack is very visible given that the exfiltration happens via a pull request. The vulnerability is patched in the `0.15.9` release of `@backstage/plugin-scaffolder-backend`.

Timeline

dates in UTC

2021-10-1821:15CVE publishedNVD

Observed activity

isMalicious corpus · updated 2026-10-23 21:37 UTC

Indicators tagged with this CVE, per day0 indicators over 7 days

Block these indicators

Firewall list (EDL, text): https://api.ismalicious.com/edl/cve/CVE-2021-41151?format=txt
CSV export: https://api.ismalicious.com/edl/cve/CVE-2021-41151?format=csv
TAXII collection of exploited CVEs
The EDL and CSV take an API key on the Pro plan.

Versions per branch

NVD · OSV

Linuxfoundation backstage

Branch	Affected	Fixed in	Source
0.x	≥ 0.9.4, < 0.15.9	0.15.9	NVD · OSV

as publishedRanges as NVD and OSV publish them; a distribution’s build can be fixed under an older number.

Fix

Update Linuxfoundation backstage to 0.15.9

Advisories and patches

github.comPatch

Detection

Nuclei template: none so far
Exploit-DB: no entry
Proof-of-concept repositories: none listed

Sources

CNACVSS 3.16.8read 2026-10-23
NVDCVSS 3.14.9read 2026-10-23
NVDCVSS 2.04read 2026-10-23
CNAweakness (CWE)CWE-22read 2026-10-23
NVDweakness (CWE)CWE-22read 2026-10-23
FIRST EPSSEPSS score1.3 %2026-10-23
OSVaffected packages—

Technical details

CVSS v3 Vector: CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:N/A:N
Published: 2021-10-18
Last Modified: 2026-06-17
NVD status: Undergoing Analysis

Frequently asked questions

What is CVE-2021-41151?

Is CVE-2021-41151 actively exploited?

Active exploitation of CVE-2021-41151 has not been confirmed. Its EPSS score was 1.3% on 2026-10-23, the estimated probability of exploitation in the next 30 days.

What is the CVSS score for CVE-2021-41151?

CVE-2021-41151 has a CVSS v3 base score of 4.9 (MEDIUM severity), with vector string CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:N/A:N.

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