How One Uncaught Rust Exception Took Out Cloudflare

On November 18 of 2025 a large part of the Internet suddenly cried out and went silent, as Cloudflare’s infrastructure suffered the software equivalent of a cardiac arrest. After much panicked debugging and troubleshooting, engineers were able to coax things back to life again, setting the stage for the subsequent investigation. The results of said investigation show how a mangled input file caused an exception to be thrown in the Rust-based FL2 proxy which went uncaught, throwing up an HTTP 5xx error and thus for the proxy to stop proxying customer traffic. Customers who were on the old FL proxy did not see this error.

The input file in question was the features file that is generated dynamically depending on the customer’s settings related to e.g. bot traffic. A change here resulted in said feature file to contain duplicate rows, increasing the number of typical features from about 60 to over 200, which is a problem since the proxy pre-allocates memory to contain this feature data.

While in the FL proxy code this situation was apparently cleanly detected and handled, the new FL2 code happily chained the processing functions and ingested an error value that caused the exception. This cascaded unimpeded upwards until panic set in: thread fl2_worker_thread panicked: called Result::unwrap() on an Err value

The Rust code in question was the following:

The obvious problem here is that an error condition did not get handled, which is one of the most basic kind of errors. The other basic mistake seems to be that of input validation, as apparently the oversized feature file doesn’t cause an issue until it’s attempted to stuff it into the pre-allocated memory section.

As we have pointed out in the past, the biggest cause of CVEs and similar is input validation and error handling. Just because you’re writing in a shiny new language that never misses an opportunity to crow about how memory safe it is, doesn’t mean that you can skip due diligence on input validation, checking every return value and writing exception handlers for even the most unlikely of situations.

We hope that Cloudflare has rolled everyone back to the clearly bulletproof FL proxy and is having a deep rethink about doing a rewrite of code that clearly wasn’t broken.

hackaday.com/2025/11/20/how-on…

Gilbert Cell Lacks Sullivan

If you’ve ever used an NE602 or similar IC to build a radio, you might have noticed that the datasheet has a “gilbert cell” mixer. What is that? [Electronics for the Inquisitive Experimenter] explains them in a recent video. The gilbert cell is a multiplier, and multiplying two waveforms will work to mix them together.

At the heart of the gilbert cell is essentially three differential amplifiers that share a common current source. The video shows LTSpice simulations of the circuits as he explains them.

One reason these work well on ICs is that they require very closely-matched transistors. In real life, it is hard to get transistors that match exactly. But when they are all on the same slab of silicon, it is fairly straightforward.

What we really like is that after simulating and explaining the circuit, he explains why multipliers mix signals, then builds a real circuit on the bench using discrete transistors and matched transistor arrays. There is a bit of trigonometry in the explanation, but nothing too difficult.

Of course, the most common application of differential amplifiers is the op amp. The NE602 is out of production, sadly, but if you can find any, they make dandy receivers.

youtube.com/embed/mQ36yy7mloA?…

hackaday.com/2025/11/20/gilber…

Wear this RISC V, RPN Calculator Watch for Maximum Nerd Cred

Once upon a time, owning a calculator watch was the epitome of cool. Well, for a very specific subset of the population with our own definition of “cool” anyway. The only thing cooler than wearing a calculator watch? Making a calculator watch, of course! If you do it as part of developing your own SDK for a popular RISC V microcontroller, all the better. That’s what [Miroslav Nemecek] did with his Antcalc watch, which is one of the demo projects for the CH32Lib SDK, which is currently under development at version 0.35 as this is written.
It appears as though the solid core wire on the back of the homemade PCB is used to hold the watch band, a nice little hack.
As you might guess, CH32LibSDK is targeting the super-cheap CH32 series of RISC V microcontrollers. Perhaps because the SDK is so early in development, there’s not much documentation outside of the example projects. The examples are all worth looking at, but our tipster wanted us to cover the Antcalc calculator watch specifically.

The Antcalc watch uses the SOP16-packaged CH32V002A4M6 to drive a small OLED display while taking input in Reverse Polish Notation from a dozen small buttons. We’re not sure how the cool kids feel about RPN these days, but that’s got to be worth extra nerd cred. Using a RISC V chip doesn’t hurt in that department, either.

For something so small– 30 mm x 55 mm–it’s looks like a decent little calculator, with 10 registers holding a mantissa of 21 digits and exponents up-to +/-99 in binary coded decimal. Seven layers on the dozen-key input pad mean most of the scientific functions you could ask for are available, along with the ability to record and replay upto 10 macros. There are also ten memory slots, all of which go into the chip’s onboard flash so are non-volatile during a battery swap. (Of which many will be necessary, since this appears to run on a single coin cell.)

If you get bored of wrist-mounted calculating, you could always repurpose this microcontroller to play MOD files on your wrist. Some people couldn’t imagine ever getting bored by a wrist-mounted calculator, and just for them we have this teardown of a beautiful 1975 model and a this article on the history of the calculator watch.

Thanks to [James Bowman] for the tip.

hackaday.com/2025/11/20/wear-t…

Centinaia di robot in marcia: la Cina presenta la nuova generazione umanoide

UBTECH Robotics, società con base a Shenzhen, ha mostrato pubblicamente la sua nuova ondata di robot umanoidi, consegnandone alcune centinaia in un’unica operazione.

L’annuncio è stato accompagnato da un video che ha rapidamente attirato l’attenzione dei social. Le riprese, realizzate all’interno di un grande magazzino completamente bianco, immortalano lunghi schieramenti di robot impegnati in movimenti sincronizzati: estraggono e reinseriscono la batteria posta sulla schiena, si siedono insieme e poi avanzano in fila verso i camion incaricati del trasporto.

Secondo l’azienda, si tratta della prima consegna su larga scala della seconda generazione dei propri modelli umanoidi, un passaggio considerato strategico per la produzione industriale. La clip si chiude con la parola “Forward”, quasi un motto che accompagna il debutto operativo dei nuovi robot.

La diffusione del filmato ha generato reazioni di segno opposto: c’è chi lo ha accolto con meraviglia e chi, invece, ha espresso una certa inquietudine. Alcuni utenti hanno persino messo in dubbio l’autenticità dell’opera, ipotizzando che potesse trattarsi di una sequenza creata digitalmente, complice l’atmosfera che ricorda le scenografie dei film di fantascienza.

I robot umanoidi sono pensati per imitare postura, movimento e operatività degli esseri umani, così da poter lavorare in ambienti condivisi. Il loro percorso parte da lontano: nel 1973 l’Università di Waseda, in Giappone, presentò Wabot-1, considerato il primo umanoide completo mai costruito. Da allora, la ricerca non si è fermata e oggi la Cina è fra i Paesi che spingono maggiormente sulla robotica avanzata.

Accanto all’interesse tecnologico, riaffiorano però timori legati al futuro del lavoro. La possibilità che macchine di questo tipo possano sostituire ruoli ripetitivi o faticosi alimenta dubbi sulle ricadute economiche per chi occupa mansioni meno qualificate, che rischiano di essere le più esposte alla competizione con robot sempre attivi e privi di costi salariali.

L’iniziativa di UBTECH si inserisce inoltre nel già teso confronto tecnologico tra Cina e Stati Uniti. La rapida crescita del settore robotico cinese viene seguita con attenzione da Washington, che da anni contende a Pechino la leadership in campi come semiconduttori, intelligenza artificiale e automazione. Resta ora da capire quale sarà la risposta statunitense di fronte a un passo avanti considerato rilevante in un settore strategico per entrambe le potenze.

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