Headline
CVE-2021-41088: Remote code execution via the web UI backend
Elvish is a programming language and interactive shell, combined into one package. In versions prior to 0.14.0 Elvish’s web UI backend (started by elvish -web) hosts an endpoint that allows executing the code sent from the web UI. The backend does not check the origin of requests correctly. As a result, if the user has the web UI backend open and visits a compromised or malicious website, the website can send arbitrary code to the endpoint in localhost. All Elvish releases from 0.14.0 onward no longer include the the web UI, although it is still possible for the user to build a version from source that includes the web UI. The issue can be patched for previous versions by removing the web UI (found in web, pkg/web or pkg/prog/web, depending on the exact version).
Impact
Elvish’s backend for the experimental web UI (started by elvish -web) hosts an endpoint that allows executing the code sent from the web UI.
The backend does not check the origin of requests correctly. As a result, if the user has the web UI backend open and visits a compromised or malicious website, the website can send arbitrary code to the endpoint in localhost.
Patches
All Elvish releases since 0.14.0 no longer include the experimental web UI, although it is still possible for the user to build a version from source that includes it.
The issue can be patched for previous versions by removing the web UI (found in web, pkg/web or pkg/prog/web, depending on the exact version).
Workarounds
Do not use the experimental web UI.
For more information
If you have any questions or comments about this advisory, please email [email protected].