Incident March 30th, 2026 – Accidental CDN Caching
blog.railway.com
blog.railway.com
"0.05% of domains" is a vanity metric -- what matters is how many requests were mis-served cross-user. "Cache-Control was respected where provided" is technically true but misleading when most apps don't set it because CDN was off. The status page is more honest here too: they confirmed content without cache-control was cached.
They call it a "trust boundary violation" in the last line but the rest of the post reads like a press release. No accounting of what data was actually exposed.
I've gone ahead and re-added the surrogate keys statement to the press release. Thank you for the feedback and if there's other things that you believe can be better please let me know!
- Why were they making CDN changes in prod? With their 100M funding recently they could afford a separate env to test CDN changes. Did their engineering team even properly understand surrogate keys to feel confident to roll out a change in prod? I don't think they're beating the AI allegations to figure out CDN configs, a human would not be this confident to test surrogate keys in prod.
- During and post-incident, the comms has been terrible. Initial blog post buried the lede (and didn't even have Incident Report in the title). They only updated this after negative feedback from their customers. I still get the impression they're trying to minimise this, it's pretty dodgy. As other comments mentioned, the post is vague.
- They didn't immediately notify customers about the security incident (people learned from their users). The apparently have emailed affected customers only, many hours after. Some people that were affected that still haven't been emailed, and they seem to be radio silent lately.
- Their founder on twitter keeps using their growth as an excuse for their shoddy engineering, especially lately. Their uptime for what's supposed to be a serious production platform is abysmal, they've clearly prioritised pushing features over reliability https://status.railway.com/ and the issues I've outlined here have little to do with growth, and more to do with company culture.
Honestly, I don't think railway is cut out for real production work (let alone compliance deployments), at least nothing beyond hobby projects.
Their forum is also getting heated, customers have lost revenue, had medical data leaked etc., with no proper followup from the railway team
https://station.railway.com/questions/data-getting-cached-or...
I've been trying to defend railway since we built our initial prototype there and I wanted to avoid the cost of migrating to some "serious infra" until proven needed, but they have been making their defense a really hard job (without mentioning that their overall reliability has been really bad the past weeks)
> Why were they making CDN changes in prod? With their 100M funding recently they could afford a separate env to test CDN changes. Did their engineering team even properly understand surrogate keys to feel confident to roll out a change in prod? I don't think they're beating the AI allegations to figure out CDN configs, a human would not be this confident to test surrogate keys in prod.
We went deep on them, tested them prior, and then when rubber met road in production we ran into cases we didn't see in testing. The large issue, and mentioned in the blogpost, is that we didn't have a mechanism to to a staged release.
> During and post-incident, the comms has been terrible. Initial blog post buried the lede (and didn't even have Incident Report in the title). They only updated this after negative feedback from their customers. I still get the impression they're trying to minimise this, it's pretty dodgy. As other comments mentioned, the post is vague.
Our initial post definitely could have been more clear, and we revised it the moment we got customer feedback to do so.
> They didn't immediately notify customers about the security incident (people learned from their users). The apparently have emailed affected customers only, many hours after. Some people that were affected that still haven't been emailed, and they seem to be radio silent lately.
We notified customers even before we did a wide release, as is process for anything security related. You create space for as much disclosure area as possible, and then follow up with a public disclosure
> Their founder on twitter keeps using their growth as an excuse for their shoddy engineering, especially lately. Their uptime for what's supposed to be a serious production platform is abysmal, they've clearly prioritised pushing features over reliability https://status.railway.com/ and the issues I've outlined here have little to do with growth, and more to do with company culture.
Do you have any specifics here? We're scaling the system at 100x YoY growth right now, working 24/7 to scale the entire thing. Again, all ears on if you have specific crits as we're always open to receiving feedback on how we can do things better!
> Their forum is also getting heated, customers have lost revenue, had medical data leaked etc., with no proper followup from the railway team
There are team members in that thread linked, are you certain you linked the right thread? Happy to have a look at anything you believe we're missing!
> We went deep on them, tested them prior, and then when rubber met road in production we ran into cases we didn't see in testing. The large issue, and mentioned in the blogpost, is that we didn't have a mechanism to to a staged release.
Honestly for a production-grade _platform_ company, that also does compliance (SOC2/3, HIPAA etc.), not having a staged release is negligent, and how you guys are handling this is a huge red flag. I've done such changes myself in production envs, for deployments that don't have the stakes you guys have. I'm normally more sympathetic on incidents, but the lack of transparency thus far from railway leaves me doubting more than anything.
> Our initial post definitely could have been more clear, and we revised it the moment we got customer feedback to do so.
Please read the room, there's still a lot of confusion about the blog post in this thread (https://news.ycombinator.com/item?id=47582295). The technical detail isn't there, we only know it about the surrogate keys from the status incident (https://status.railway.com/incident/X0Q39H56) which is not linked in the post. The blog post reads like PR compared to the initial incident status report, and the resolved timestamp does not match which is sloppy. Your little edit to the title only made it from a bad post to a slightly less bad post.
> We notified customers even before we did a wide release, as is process for anything security related. You create space for as much disclosure area as possible, and then follow up with a public disclosure
Emailing only affected users isn't working out, because affected people aren't yet emailed (I know one personally). Just check the post on your own forum (https://station.railway.com/questions/data-getting-cached-or... did you actually read it?) and see the list of people affected still not emailed, and left on read. You guy should email everyone, this is a security incident not a service interruption. There's a lot of loss trust by your customers now, i.e., if you guys can't figure out who to email, what else are you doing wrong?
> Do you have any specifics here? We're scaling the system at 100x YoY growth right now, working 24/7 to scale the entire thing. Again, all ears on if you have specific crits as we're always open to receiving feedback on how we can do things better!
https://x.com/JustJake/status/2038806338915152350
Again, it's not an excuse if you're a _platform_ company that customers pay a lot of money to be reliable. You can't just keep saying you're open to feedback and being transparent as vanity. There's plenty of feedback on here, your twitter, your forum, and feedback is people are telling you to focus on reliability, because railway keeps breaking their deployments. If you don't care about reliability and prefer to scale with features, be honest about it. Railway's poor uptime does not lie.
> There are team members in that thread linked, are you certain you linked the right thread? Happy to have a look at anything you believe we're missing!
Did you read the thread? Yes, only _one_ employee commented 5 hours after my HN comment. Still almost everyone left of read, unanswered questions etc.
By way that's only one forum post, there are many that are just ignored, one where a user mentioned they're reporting railway to ICO for a GDPR breach, rightfully.
We do indeed have a staging environment as mentioned previously. The issue arose in the rollout to production as mentioned previously.
> The blog post reads like PR compared to the initial incident status report, and the resolved timestamp does not match which is sloppy.
I've gone ahead and added the surrogate key mention into the post mortem. We initially got in trouble for having it be too technical centric and not enough on the user impact. It's a delicate balance; apologies. As I mention, we are open to critical feedback here.
> Emailing only affected users isn't working out, because affected people aren't yet emailed (I know one personally). Just check the post on your own forum (https://station.railway.com/questions/data-getting-cached-or... did you actually read it?) and see the list of people affected still not emailed, and left on read.
We have people working directly in that thread. For anybody who believes they were affected but not reached out to, we're working directly with them. We do take this very seriously. If you know someone here, please have them reach out either there or directly to me at jake@railway.com
> Again, it's not an excuse if you're a _platform_ company that customers pay a lot of money to be reliable. You can't just keep saying you're open to feedback and being transparent as vanity.
In the directly linked tweet I've mentioned that we're focusing on scaling the current system vs adding new features. We absolutely do need to do better on reliability, and my point is "Is there a specific poor engineering practice you're seeing here, or is it just based on reliability". Either is a fine crit we just want to make sure all our basis are covered
> Did you read the thread? Yes, only _one_ employee commented 5 hours after my HN comment. Still almost everyone left of read, unanswered questions etc.
Indeed I've read the thread, and we have people working it (you can see as of 8 hours ago).
You may have misunderstood, I said staged release, i.e., I'm referencing the rollout
> I've gone ahead and added the surrogate key mention into the post mortem. We initially got in trouble for having it be too technical centric and not enough on the user impact. It's a delicate balance; apologies. As I mention, we are open to critical feedback here.
You can do both. If you have different audiences, have two separate posts and mutually link to redirect audiences. Ask your sec staff instead of relying on paying customers to give post-hoc feedback on your dodgy disclosure practices. If I have ping a platform company to correct and clarify info about their security disclosure, I'm out.
From the outside, it looks like "just a cache misconfiguration," but in reality, the problem is more insidious because it's distributed across multiple layers: - application logic (authentication limitations) - CDN behavior -> infrastructure - default settings that users rely on (no cache headers because the CDN was disabled)
The hardest part of debugging these cases isn't identifying what happened, but realizing where the model is flawed: everything appears correct locally, the logs don't report any issues, yet users see completely different data.
I've seen similar cases where developers spent hours debugging the application layer before even considering that something upstream was silently changing the behavior.
These are the kind of incidents where the debugging path is anything but linear.
There are dozens of contradictions, like first they say:
“this may have resulted in potentially authenticated data being served to unauthenticated users”
and then just a few sentences later say
“potentially unauthenticated data is served to authenticated users”
which is the opposite. Which one is it?
Am I missing something, or is this article poorly reviewed?
https://x.com/JustJake/status/2007730898192744751
I wouldn't be surprised if most of Railway's infra is running on Claude at this point.
A lot of people are confident in enough in their ability to spot AI infra that they are willing to dismiss a firsthand source on this, and I admit I have no idea why. There isn't any upside to making this claim, and anyway, I assure you that people need no help at all from AI to make these kinds of mistakes.
I'm sure Claude didn't literally ship the feature itself with no oversight, but I also find it hard to believe that their approach to adopting AI didn't factor in at all. Even just like, the mental overhead of moving faster and adopting AI code with less stringent review leading to an increase in codebase complexity could cause it. Couple that with an AI hallucinating an answer to the engineer who shipped this change, I'm not sure why people are so quick to discount this as a potential source of the issue. Surely none of us want our infra to become less secure and reliable, and so part of preventing that from happening is being honest about the challenges of integrating AI into our development processes.
Because (per the link above) the CEO said that (1) it was their fault, and (2) it had nothing to do with AI.
I understand that on this forum statements like this are inevitably greeted with some amount of skepticism, but right now I'm seeing no particular reason to disbelieve Jake, and the reason that "if they did use AI they'd deny it" should frankly not be considered good enough to fly around here. Like probably everyone in this comment section I'm open to evidence that they used AI to slop-incident themselves, but until we can reach that standard let's please calm down and focus on what we actually know to be true.
In my life I have gone back and forth on the idea that 12 angry men is a kind of facile representation of how people think and what kinds of evidence really form the basis of a reasonable society. This comment section is doing a really good job of stretching my resolve to believe we are getting at least better.
Be more direct. Be concise. This blog post sounds like a cagey customer service CYA response. It defeats the purpose of publishing a blog post showing that you’re mature, aware, accountable, and transparent.
(also looks like two versions of the 'postmortem' are published at https://blog.railway.com/engineering)
I think this is their first major security incident. Good that they are transparent about it.
If possible (@justjake) it would be helpful to understand if there was a QA/test process before the release was pushed. I presume there was, so the question is why this was not caught. Was this just an untested part of the codebase?
We've rolled out some changes (detailed in the blogpost) which should avoid this in the future. Deepest apologies
I think that's already best practice in most API designs anyway?
No, it isn't. Ive not seen this in an API ever and only in webapps ?phpsessid= back in childhood