To be clear: The November 2025 Cloudflare outage had a database misconfiguration as its root cause - a permissions change that caused duplicate entries in their Bot Management feature file. However, what turned this configuration error into a global internet outage was a Rust unwrap() that panicked when the file exceeded expected limits. The database issue was the match; the unwrap() was the powder keg. This distinction actually strengthens the article’s central argument: Rust’s marketing about “safety” creates false expectations that even routine operational errors won’t cause catastrophic failures. The language worked exactly as designed - it prevented memory corruption while panicking cleanly. But “working as designed” still took down major internet services, because the design was never what the marketing implied.
In February 2019, a Rust developer named sanxiyn posted a provocative proposal to the Rust Internals forum: “eliminate wording ‘memory safety’ and ‘thread safety.’” Their reasoning was blunt:
“I think these wordings are question-begging, as their uses on, say, HN, quickly degenerate to ‘yes, leaks are memory safe’, ‘yes, deadlocks are thread safe’, and others. I found that casual readers get the impression like, ‘sure, you can prove anything if you redefine terms to whatever you want’.”
This was nearly six years before the Cloudflare outage that would prove their concerns prescient. But sanxiyn wasn’t alone. The internal discussions within Rust’s development community reveal a long-standing awareness that their marketing claims were creating dangerous misconceptions—misconceptions they chose to live with.
These aren’t hidden conversations or leaked documents. These are public discussions on Rust’s official forums that anyone can read today. The evidence of this internal contradiction has been sitting in plain sight for years. The primary sources are linked throughout this article—verify everything yourself.
The Rust Internals forum discussions from 2018-2019 paint a fascinating picture of a community grappling with the gap between technical precision and marketing effectiveness. These aren’t outsiders criticizing Rust—these are the people building it, and they knew exactly what was happening.
In August 2018, a thread titled “Let’s reword front page claims” captured the essence of the problem. Developer rpjohnst noted:
“A data race can violate memory safety, that’s why Rust bothers to prevent them. A higher-level race condition, on its own, cannot.”
This is a critical distinction that gets lost in marketing. Rust prevents data races (undefined behavior at the memory level) but not race conditions (logic errors where operations happen in the wrong order). To a systems programmer, this difference is fundamental. To a CTO reading Rust’s homepage claiming it “guarantees thread safety,” it’s invisible.
The proposed alternatives were telling. Centril suggested:
“Rust is a systems programming language that runs blazingly fast, prevents segfaults and data races.”
Note what’s missing: the word “safety.” Because even Rust’s developers understood that “safety” was being interpreted far more broadly than they intended.
But here’s where it gets interesting. Another developer, gbutler, responded with bitter sarcasm:
“I’d think if you’re going to give in to the kind of pedantry that questions the use of ‘guarantees thread-safety’ you’d probably have to have the motto be something like: ‘Rust is a programming language that runs and tries to prevent segfaults, data races, and maintain thread-safety unless you use explicitly marked ‘unsafe’ code in a way that makes it not work correctly.’ Yay for Motto’s! I say, screw the Pedants!“
This dismissive response reveals the tension: accuracy versus marketing effectiveness. The accurate description is unwieldy. The marketable description is misleading. Rust chose marketing.
Perhaps the most damning admission came from sanxiyn in the 2019 thread:
“I found that while there is no alternative technical definition, colloquial definition is really some approximation of ‘freedom from memory-related bugs’ and ‘freedom from thread-related bugs’. So ‘memory-related bug (say leak) does not contradict freedom from memory-related bugs (aka memory safety)!’ just sounds crazy.”
This is the core of the problem. Rust’s technical community uses “memory safety” to mean something very specific: absence of undefined behavior related to memory access. But the rest of the world hears “memory safety” and thinks “my program won’t have memory problems.”
earthengine tried to bridge this gap by suggesting more precise terminology:
“Maybe, the better replacement is ‘memory-related non-UB guarantee’ and ‘thread-related non-UB guarantee’.”
Imagine that on Rust’s homepage: “Rust provides memory-related non-UB guarantees!” It’s accurate. It’s also marketing suicide.
The responses defending Rust’s terminology are perhaps more revealing than the criticisms. H2CO3 wrote a lengthy defense that included this telling paragraph:
“Nobody ‘redefines’ anything (especially not maliciously or in an intentionally misleading manner), let alone redefining terms to ‘whatever they want’. Memory leaks and deadlocks do not unto themselves constitute unsafety.”
But then they immediately acknowledge:
“The fact that many people, unfamiliar with lower-level details of (systems) programming, confuse the generic notion of ‘any bug’ with the specifics of memory and thread unsafety issues is unfortunate...”
So the defense is: “We’re not redefining anything maliciously, we’re just using technical definitions that we know most people will misunderstand, and that’s unfortunate but not our fault.”
This is exactly the kind of reasoning that led to the public confusion after Cloudflare. The Rust community knew their terminology was being misunderstood. They acknowledged it was “unfortunate.” They did nothing to fix it.
In the same 2019 thread, bascule, identifying as “a security professional,” cited the famous Microsoft study:
“Microsoft: 70 percent of all security bugs are memory safety issues“
This statistic has become a cornerstone of Rust evangelism. But notice the sleight of hand: Microsoft’s study is about memory safety bugs causing security vulnerabilities. Rust prevents memory safety bugs. Therefore, Rust prevents 70% of security vulnerabilities, right?
Wrong. As the Cloudflare incident demonstrated, you can have a catastrophic security incident (a global CDN outage that could have been exploited by attackers) without a single memory safety violation. The unwrap() that crashed Cloudflare was memory-safe. It was also a critical security failure that took down major internet services.
Perhaps no Rust marketing phrase has aged worse than “fearless concurrency.” Even in 2019, bascule was skeptical in the same thread:
“’Thread safety’ I’m a lot more on the fence about (or worse its even more boastful incarnation ‘fearless concurrency’). While the static checks Rust provides to eliminate data races are great, multithreaded programs are still fraught with errors. I’m not sure ‘fearless concurrency’ applies in a language where PoisonError exists, for example, or deadlock potential.”
Think about that. A core Rust developer is essentially saying “fearless concurrency” is false advertising because:
PoisonError exists (threads can still panic and leave shared state in an inconsistent condition)
Deadlocks are still possible (and Rust does nothing to prevent them)
Multithreaded programs remain “fraught with errors”
Yet “fearless concurrency” remains one of Rust’s most prominent marketing claims to this day.
What emerges from these discussions is a pattern:
Recognition: “Our terminology is misleading people”
Rationalization: “But it’s technically correct from a systems programming perspective”
Dismissal: “Educating users is the solution, not changing our messaging”
Repetition: Continue using the misleading terminology
Ixrec suggested a middle ground:
“If we actually want to prevent potential misunderstandings of the slogan... I’d much rather we make that part of the slogan link to a comprehensive technical explanation of what ‘guarantees thread safety’ means.”
This suggestion—adding clarifying links—was never implemented. The misleading slogans remained, unqualified and unexplained.
One developer, BatmanAoD, came remarkably close to predicting the exact kind of incident that would occur at Cloudflare. They proposed this rewording:
“Rust is a systems programming language that runs blazingly fast while ensuring memory safety even for memory shared across threads. Opportunities for undefined behavior are strictly opt-in.”
Note what this formulation does:
It specifies “memory safety” not general safety
It acknowledges that undefined behavior is still possible (in unsafe blocks)
It doesn’t claim to prevent all threading problems
This would have been honest. It also would have prevented the misconceptions that made the Cloudflare incident so damaging to Rust’s reputation. It was ignored.
Throughout these discussions, a recurring defense appears: Rust is an “incremental improvement” over C++, not a silver bullet. BatmanAoD argued:
“Opt-out safety, rather than opt-in, is a huge deal in the world of low level languages.”
This is absolutely true. But it’s not what the marketing says. The marketing doesn’t say “Rust is incrementally safer than C++.” It says “Rust is safe.” Full stop.
The internal discussions reveal that Rust developers understood the nuanced reality. But the external marketing projected confident absolutism. This gap between internal understanding and external messaging is precisely what created the conditions for the Cloudflare incident to be so damaging.
The Cloudflare incident isn’t just about one company’s outage. It’s the inevitable result of a marketing strategy that Rust’s own developers knew was problematic but chose to maintain anyway.
Consider the actual timeline:
2018: Rust developers debate whether “guarantees thread safety” is misleading
2019: Developers propose eliminating “memory safety” and “thread safety” from marketing
2019-2024: No significant changes to marketing language
November 18, 2025, 11:05 UTC: Database permission change causes duplicate entries
November 18, 2025, 11:20 UTC: Rust
unwrap()panics on oversized file, crashes global CDNPost-incident: “Rust isn’t as safe as claimed” becomes the narrative
The technical sequence was: database misconfiguration → oversized feature file → unwrap() panic → global outage. But the narrative sequence was: “safe language” marketing → operational error → system crash → credibility crisis.
This wasn’t a surprise. It was predictable. Rust’s own developers predicted it. They knew that conflating “memory safety” with “operational safety” would eventually lead to exactly this kind of reputational damage.
The real tragedy here isn’t technical—it’s strategic. By choosing marketable claims over precise ones, Rust has:
Created false expectations that set up users for disappointment
Undermined its own credibility when those expectations inevitably fail
Provided ammunition to critics who can now point to real-world failures
Confused the conversation about what Rust actually provides
The internal discussions show that Rust developers knew all of this. They saw the train coming. They chose to stay on the tracks because getting off would mean admitting their marketing was overreaching.
Imagine if, in 2019, Rust had listened to sanxiyn and others. Imagine if they had:
Replaced “memory safety” with “prevents memory-related undefined behavior”
Replaced “thread safety” with “prevents data races”
Replaced “fearless concurrency” with “compiler-enforced synchronization”
Added explicit disclaimers about what isn’t prevented
The marketing would have been less sexy. Conference talks would have been harder to sell. But when Cloudflare’s database misconfiguration triggered an unwrap() panic, the response would have been: “Yes, Rust doesn’t prevent logic errors or operational mistakes. We never said it did. The database issue caused bad input, the code didn’t handle it gracefully - that’s on the developer, not the language.”
Instead, we got: “Wait, I thought Rust was supposed to be safe? How did a ‘safe’ language crash the entire internet?”
The database misconfiguration was the proximate cause. But the reputational damage came from the gap between what people expected from a “safe” language and what actually happened. That gap exists because Rust chose marketing over precision.
The most striking aspect of these internal discussions is how clearly Rust’s developers understood the problems with their marketing. They weren’t blind to it. They weren’t naive. They knew.
They knew “memory safety” would be misunderstood. They knew “thread safety” was misleading. They knew “fearless concurrency” was an overreach.
They knew, and they chose marketing effectiveness over honest communication.
This isn’t unique to Rust. Every technology makes this choice to some degree. But Rust’s case is particularly stark because:
The discussions are public and searchable
The warnings were explicit and technical
The predicted confusion has now manifested catastrophically
Don’t take my word for it—read the discussions yourself. Every quote in this article comes from these public forums. The concerns were genuine. The warnings were ignored.
The Cloudflare incident is a gift, if Rust is willing to accept it. It’s an opportunity to finally make the changes their own developers called for years ago:
Retire the misleading slogans. “Memory safety” and “thread safety” have proven to cause more confusion than clarity.
Embrace precision over marketing. “Prevents undefined behavior” is less sexy than “safe” but it’s honest.
Acknowledge the limitations explicitly. Every mention of what Rust prevents should be paired with what it doesn’t.
Listen to your own developers. When your own community is warning about messaging problems, believe them.
For the rest of us in the technology industry, the Rust situation offers a crucial lesson: marketing debt is technical debt.
Every time you oversell a capability, you’re borrowing against future credibility. Every misleading claim is a future incident report waiting to happen. Every gap between internal understanding and external messaging is a scandal in waiting.
Rust’s developers knew their marketing was creating false expectations. They documented their concerns. They proposed alternatives. And they were overruled by the imperative to sell the language.
Now, years later, the bill has come due. The Cloudflare incident didn’t just crash a CDN—it crashed a narrative that Rust’s own developers knew was unsustainable.
The Rust Internals discussions from 2018-2019 read like a prophecy of the Cloudflare incident. Developers warned that the marketing claims would create confusion. They predicted that people would feel misled when real-world failures occurred. They proposed more accurate alternatives.
They were ignored.
Yes, the Cloudflare outage started with a database misconfiguration. But thousands of database misconfigurations happen every day without taking down the internet. What made this one catastrophic was an unhandled error in code written in a language marketed as “safe.” The technical failure was mundane; the reputational damage was severe precisely because of the expectations Rust’s marketing had created.
The result is that Rust—a genuinely innovative and valuable language—now faces a credibility crisis it could have avoided. The technology is sound. The marketing was not. And the gap between them was documented, discussed, and deliberately maintained by people who knew better.
For those of us building and promoting technology, the lesson is clear: your own developers know when your marketing is lying. Listen to them. Because if you don’t, reality will eventually expose the lie, and the damage to your credibility will far exceed whatever benefit the marketing provided.
Rust prevented memory unsafety at Cloudflare. It did exactly what it was technically designed to do. But because the marketing promised more than memory safety—because it implied reliability, robustness, and “fearless” operation—the technical success became a marketing failure.
That’s the real tragedy of the Cloudflare incident: Rust worked as designed, but the design was never what the marketing claimed it was. And Rust’s own developers knew it all along.
The discussions quoted in this article are from Rust’s official internal forums:
“Proposal: eliminate wording ‘memory safety’ and ‘thread safety’” - Rust Internals Forum, February 2019
https://internals.rust-lang.org/t/proposal-eliminate-wording-memory-safety-and-thread-safety/9416“Let’s reword front page claims” - Rust Internals Forum, August 2018
https://internals.rust-lang.org/t/lets-reword-front-page-claims/8299/23
These are public discussions that anyone can verify. The evidence has been in plain sight for years.
A Note on Root Causes: Some will argue that focusing on the unwrap() rather than the database misconfiguration misses the point. But that’s precisely backwards. Every production system faces configuration errors, bad input, and operational mistakes. What distinguishes systems is how they handle these inevitable failures. Rust’s marketing implied it would make systems more resilient to such failures. Instead, an unhandled error took down critical internet infrastructure. The database error was unfortunate; the inability to handle it gracefully in a “safe” language was the scandal. And that scandal was predictable to anyone who understood the gap between Rust’s technical capabilities and its marketing claims - including, as these discussions show, Rust’s own developers.
Previous article on technical discussion here:
The Cloudflare Outage and the Rust Marketing Problem
On November 18, 2025, a significant portion of the internet went offline. X, ChatGPT, Canva, Letterboxd, and countless other services became inaccessible. The culprit? A single unwrap() call in Rust code that panicked across Cloudflare’s 330+ datacenters. The incident has sparked a predictable wave of commentary: some defending Rust’s actual guarantees, others claiming vindication that “Rust isn’t special,” and most people somewhere in between, confused about what just happened and why.