CVE-2021-43783
Path Traversal in @backstage/plugin-scaffolder-backend
@backstage/plugin-scaffolder-backend is the backend for the default Backstage software templates. In affected versions a malicious actor with write access to a registered scaffolder template is able to manipulate the template in a way that writes files to arbitrary paths on the scaffolder-backend host instance. This vulnerability can in some situation also be exploited through user input when executing a template, meaning you do not need write access to the templates. This method will not allow the attacker to control the contents of the injected file however, unless the template is also crafted in a specific way that gives control of the file contents. This vulnerability is fixed in version 0.15.14 of the @backstage/plugin-scaffolder-backend. This attack is mitigated by restricting access and requiring reviews when registering or modifying scaffolder templates.
Attack profile
How easy it is to exploit
- Attack vector
- Network
- Complexity
- Low
- Privileges needed
- Low
- User interaction
- None
What an attacker can affect
- Confidentiality
- None
- Integrity
- High
- Availability
- Low
Exploit likelihood
What each source reports
CVE List Score used
Path Traversal in @backstage/plugin-scaffolder-backend
@backstage/plugin-scaffolder-backend is the backend for the default Backstage software templates. In affected versions a malicious actor with write access to a registered scaffolder template is able to manipulate the template in a way that writes files to arbitrary paths on the scaffolder-backend host instance. This vulnerability can in some situation also be exploited through user input when executing a template, meaning you do not need write access to the templates. This method will not allow the attacker to control the contents of the injected file however, unless the template is also crafted in a specific way that gives control of the file contents. This vulnerability is fixed in version 0.15.14 of the @backstage/plugin-scaffolder-backend. This attack is mitigated by restricting access and requiring reviews when registering or modifying scaffolder templates.
- Record
CVE-2021-43783- CVSS 3.1
- 8.5 High
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:N/I:H/A:L - Weakness
- CWE-22
- Updated
- 2026-11-02
EUVDEUVD-2021-2554
@backstage/plugin-scaffolder-backend is the backend for the default Backstage software templates. In affected versions a malicious actor with write access to a registered scaffolder template is able to manipulate the template in a way that writes files to arbitrary paths on the scaffolder-backend host instance. This vulnerability can in some situation also be exploited through user input when executing a template, meaning you do not need write access to the templates. This method will not allow the attacker to control the contents of the injected file however, unless the template is also crafted in a specific way that gives control of the file contents. This vulnerability is fixed in version 0.15.14 of the @backstage/plugin-scaffolder-backend. This attack is mitigated by restricting access and requiring reviews when registering or modifying scaffolder templates.
- Record
EUVD-2021-2554- CVSS 3.1
- 8.5 High
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:N/I:H/A:L - Updated
- 2026-11-03
GitHub AdvisoriesGHSA-mg3m-f475-28hv
Path Traversal in @backstage/plugin-scaffolder-backend
Impact
A malicious actor with write access to a registered scaffolder template is able to manipulate the template in a way that writes files to arbitrary paths on the scaffolder-backend host instance.
This vulnerability can in some situation also be exploited through user input when executing a template, meaning you do not need write access to the templates. This method will not allow the attacker to control the contents of the injected file however, unless the template is also crafted in a specific way that gives control of the file contents.
Patches
This vulnerability is fixed in version 0.15.14 of the @backstage/plugin-scaffolder-backend.
Workarounds
This attack is mitigated by restricting access and requiring reviews when registering or modifying scaffolder templates.
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
- Record
GHSA-mg3m-f475-28hv- CVSS 3.1
- 8.5 High
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:N/I:H/A:L - Weakness
- CWE-22
- Updated
- 2026-11-02
NVD
@backstage/plugin-scaffolder-backend is the backend for the default Backstage software templates. In affected versions a malicious actor with write access to a registered scaffolder template is able to manipulate the template in a way that writes files to arbitrary paths on the scaffolder-backend host instance. This vulnerability can in some situation also be exploited through user input when executing a template, meaning you do not need write access to the templates. This method will not allow the attacker to control the contents of the injected file however, unless the template is also crafted in a specific way that gives control of the file contents. This vulnerability is fixed in version 0.15.14 of the @backstage/plugin-scaffolder-backend. This attack is mitigated by restricting access and requiring reviews when registering or modifying scaffolder templates.
- Record
CVE-2021-43783- CVSS 3.1
- 8.5 High
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:N/I:H/A:L - CVSS 2.0
- 5.5 Medium
AV:N/AC:L/Au:S/C:N/I:P/A:P - Weakness
- CWE-22
- Updated
- 2026-11-02
OSV
@backstage/plugin-scaffolder-backend is the backend for the default Backstage software templates. In affected versions a malicious actor with write access to a registered scaffolder template is able to manipulate the template in a way that writes files to arbitrary paths on the scaffolder-backend host instance. This vulnerability can in some situation also be exploited through user input when executing a template, meaning you do not need write access to the templates. This method will not allow the attacker to control the contents of the injected file however, unless the template is also crafted in a specific way that gives control of the file contents. This vulnerability is fixed in version 0.15.14 of the @backstage/plugin-scaffolder-backend. This attack is mitigated by restricting access and requiring reviews when registering or modifying scaffolder templates.
- Record
CVE-2021-43783- CVSS 3.1
- 8.5 High
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:N/I:H/A:L - Updated
- 2026-11-02
OSVGHSA-mg3m-f475-28hv
Path Traversal in @backstage/plugin-scaffolder-backend
Impact
A malicious actor with write access to a registered scaffolder template is able to manipulate the template in a way that writes files to arbitrary paths on the scaffolder-backend host instance.
This vulnerability can in some situation also be exploited through user input when executing a template, meaning you do not need write access to the templates. This method will not allow the attacker to control the contents of the injected file however, unless the template is also crafted in a specific way that gives control of the file contents.
Patches
This vulnerability is fixed in version 0.15.14 of the @backstage/plugin-scaffolder-backend.
Workarounds
This attack is mitigated by restricting access and requiring reviews when registering or modifying scaffolder templates.
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
- Record
GHSA-mg3m-f475-28hv- CVSS 3.1
- 8.5 High
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:N/I:H/A:L - Weakness
- CWE-22
- Updated
- 2026-11-02
Affected products
Affected packages
| Package | Affected | Fixed |
|---|---|---|
@backstage/plugin-scaffolder-backendnpm |
before 0.15.14 | 0.15.14 |
History
| Recorded | Changed | Sources |
|---|---|---|
| aliases | EUVD | |
| first indexed | CVE List, GitHub Advisories, NVD, OSV |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2021-43783 is a high vulnerability (CVSS 8.5) in Backstage, published November 29, 2021. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 1.25%, the 69th percentile. Fixed in @backstage/plugin-scaffolder-backend 0.15.14.