Comment by btown
1 day ago
Via the incident page:
> Environment variables marked as "sensitive" in Vercel are stored in a manner that prevents them from being read, and we currently do not have evidence that those values were accessed. However, if any of your environment variables contain secrets (API keys, tokens, database credentials, signing keys) that were not marked as sensitive, those values should be treated as potentially exposed and rotated as a priority.
https://vercel.com/kb/bulletin/vercel-april-2026-security-in... as of 4:22p ET
The “sensitive” toggle is off by default. I’m curious about the rationale, what's the benefit of this default for users and/or Vercel?
https://vercel.com/docs/environment-variables/sensitive-envi...
Simpler for vibe coders.
Ok but it's not the original intent: that default exists since at least 2020: https://web.archive.org/web/20201130022511/https://vercel.co...
Sensitive environment variables are environment variables whose values are non-readable once created.
So they are harder to introspect and review once set.
It’s probably good practice to put non-secret-material in non-sensitive variables.
(Pure speculation, I’ve never used Vercel)
I have used Vercel though prefer other hosts.
There are cases where I want env variables to be considered non-secure and fine to be read later, I have one in a current project that defines the email address used as the From address for automated emails for example.
In my opinion the lack of security should be opt-in rather than opt-out though. Meaning it should be considered secure by default with an option to make it readable.
How does the app read the variable if it can't be read after you input it? Or do they mean you can't view it after providing the variable value to the UI?
They mean the latter. Very unclear how that translates to meaningful security.
You could have a meaningful wall between administrative/deployment interface backends and the customer server backends - only the latter get access to services that have the private keys to decrypt the at-rest storage of secure variables, and this may be fully isolated to different control planes. So it becomes write-but-not-read.
But that's just a bare-minimum defense-in-depth. The fact that an attacker was able to access the insecure variables, and likely the names of secure variables, is still horrifying.