👶 From when Mosaic took over Gopher 🏢 VP of Engineering @cloudflare 🇵🇹 Lisbon, Portugal

Lisbon, Portugal
Joined March 2007
Celso Martinho retweeted
🚨 Damage to two international fiber links on Route Nationale 1 in #Haiti caused a complete #Internet outage on Digicel Haiti (AS27653). Traffic dropped to zero at ~17:15 UTC (13:15 local) on Oct 27 and remains down. Follow the latest on Cloudflare Radar: radar.cloudflare.com/traffic…
Nap enfòme kliyan nou yo, ke @DigicelHT sibi de domaj sou lyen fib optik entènasyonal li yo sou wout nasyonal 1. Koupi sa yo afekte sèvis entènèt sou tout teritwa a. Ekip nou idantifye zòn domaj yo e ap evalye koman pou aksede zòn lan ki vin ankò pi volatil!
1
4
2
12
1,965
Celso Martinho retweeted
A national grid fault cut power to eastern Dhaka and parts of Chattogram in #Bangladesh, impacting #Internet connectivity. Starting ~06:45 UTC (12:45 local), traffic fell by as much as ~25%. radar.cloudflare.com/traffic…
2
5
8
1,701
Celso Martinho retweeted
Time to test and brag about your harness and agent! 🧪 Limited-time Cloudflare PHP WAF CTF: $3K per eligible, unique report. RCE → flag → UI verification. POST-only testing. CTF: php-rce.cloudflare.app/ blog.cloudflare.com/php-ctf/ PS: Can’t submit on HackerOne? Please don’t DM me. #PHP2Shell #ctf #Cloudflare
1
1
152
Celso Martinho retweeted
A lot of folks have asked for Spend management limits on @Cloudflare for some time now I've spent the last three months rebuilding our billing usage platform to enable this for our product catalog starting with Workers and Durable Objects and I'm pleased to give you a quick sneak peek 🫣 Shipping on Cloudflare for humans and agents shortly along with an engineering deep dive on how we did it Send me or @irvinebroque a DM if you want to try it early
104
61
39
664
68,055
Celso Martinho retweeted
We are launching a PHP Capture the Flag challenge integrated with our Bug Bounty program to test our WAF protections. Security researchers are invited to bypass our defenses and capture the flag to help make the Internet safer. cfl.re/4iqHaQ1
30
114
32
781
201,403
Celso Martinho retweeted
Always have enjoyed CTFs. So I Asked the team to build one for the php2shell CVEs. Stock PHP 8.5.11 behind our WAF with default rules. Find a way around and read /flag and report to earn bounty. REMINDER - WAF buys you time. It isn't bulletproof. Upgrade your PHP. blog.cloudflare.com/php-ctf
15
60
12
560
58,626
Celso Martinho retweeted
today was my last day in cloudflare (again). the best career and opportunity in my whole life, and the closest friends I would die for. thank you to everyone who made it all so special. I had an incredible time. 🧡
219
90
94
6,971
901,295
Celso Martinho retweeted
Pick your cofounders carefully and everything else is so much more fun!
27
13
2
675
48,274
Celso Martinho retweeted
Two classes extremely bad cyber vulnerabilities disclosed in the last 24 hours. The first potentially impacts everyone online. The second impacts nearly everyone running a server. tl;dr: Everyone should upgrade their OS and Browser as soon as possible. If you run a server you should upgrade PHP (or ensure it’s removed if you’re not using it) as soon as possible. The first class of vulnerabilities is a set of root TLS certificates that were discovered to have a trivial private key. Literally the number 4. These roots were controlled by #eMudhra. The problem is that with that an attacker could create a certificate and, if they could get in the traffic flow, intercept traffic to any site or service. The solution is to stop trusting certificates issued by these vulnerable roots. Upgrading your browser and OS is the fastest way for most Internet users to do this. The second class of vulnerabilities doesn’t apply to most consumers directly, but does apply to most anyone running a server. These vulnerabilities have been dubbed #php2shell. PHP is one of the most widely used web programming languages. It’s estimated 70% of websites run on PHP. These vulnerabilities allow an attacker to send a crafted set of queries to a server running PHP and potentially take over the server. From there they could potentially read, modify, delete, or repurpose anything on the server. The solution is to upgrade PHP to the latest version ASAP. Even if you’re not using PHP for your web development, it’s often included by default. So make sure it is either upgraded or fully removed. @Cloudflare received advanced warning of both of these classes of vulnerabilities. We’ve ensured that where we act as a proxy we are no longer trusting the vulnerable roots. We are also reviewing certificate transparency (CT) logs for any sign the vulnerability was exploited before its disclosure. We have not found any evidence but CT logs are not perfect and a sophisticated attacker who knew about the weakness could have exploited it without a new certificate being logged. For the PHP vulnerabilities, we have deployed mitigations available for all customers for free. Because of the complexity of the vulnerabilities and number of ways it can be exploited, we also released new WAF capabilities that are unique in the industry to catch the exploit based on the response. These too are available for every Cloudflare customer for free. Even if you are taking advantage of Cloudflare’s protection, it is important to upgrade your OS, browsers, and PHP installations as soon as possible. We can provide a strong bandaid, but the best protection is to fix the underlying problem. If you’re interested in learning more, you can read our blogs: Vulnerable roots: blog.cloudflare.com/emudhra-… PHP vulnerabilities: blog.cloudflare.com/php-vuln…
86
764
96
4,551
672,476
Celso Martinho retweeted
one thing that made this click for me — with decision models, you have to define categories and it returns probabilities that the input matches those categories. but so much of the data we interact with is completely new to us. how can you define categories for something you've never read? with clairic, you can extract values directly from the inputs, without any premeditated categories. the pipeline becomes clairic to extract values → clef to make decisions with those values → LLMs to take actions on those decisions. all of these models run on Workers AI.
23
65
12
900
40,724
🚨 Google Cloud's europe-west2 (London) region has seen a sharp rise in connection failures since 06:00 UTC on Oct 20. #Internet Follow the latest on Cloudflare Radar: radar.cloudflare.com/cloud-o…
7
66
7
409
33,116
Celso Martinho retweeted
Putting the final touches on Moscone West for #CloudflareConnect 2026! 🛠️🍊 From the big signs to the indoor setups, we’re getting everything ready for you. Can't wait to see you all! 👋☁️
12
9
7
111
20,333
Celso Martinho retweeted
Replying to @CFchangelog
Multilingual search support is a big step forward. Making AI search work naturally across more languages opens the door to a much wider range of users.
1
1
208
AI Search keyword search now supports Japanese, Chinese, and Korean queries via the trigram tokenizer. Set keyword_tokenizer to trigram for full natural language search support. developers.cloudflare.com/ch…
3
12
3
57
3,916
Celso Martinho retweeted
Kitesurf is a browser that runs inside a @Cloudflare Worker. No Chromium, no container. @mattzcarey demoed an agent driving it live at init().
4
10
5
97
12,193
Celso Martinho retweeted
Introducing Void: an open-source SDK, CLI, and self-hosted platform for building full-stack Vite apps and deploying them to Cloudflare. cfl.re/47ny0OX
36
124
28
1,228
120,805
Celso Martinho retweeted
This is a big deal to define a path toward making the future agentic Internet sustainable.
Today, Cloudflare and @OpenAI released the first findings from their joint research pilot, demonstrating how real-time network signals can make AI search drastically smarter, fresher, and safer without overloading website infrastructure. cfl.re/4zUxVPd
7
11
2
193
27,839
new tools in the cloudflare agents sdk web_search powered by the new Cloudflare Web Search API - use exa, linkup, or ceramic via AI Gateway developers.cloudflare.com/ch… web_fetch with automatic markdown conversion developers.cloudflare.com/ch… works with pi-durable or any other harness npm i agents
6
15
4
160
7,139
The third Yandex data center hit by drones since Oct 7. Traffic from YANDEX (AS13238) was already ~35% lower after the Sasovo strike, then fell 99% vs. last week at ~00:30 UTC Oct 11, as its Vladimir site shut down, per the company. Follow along: radar.cloudflare.com/traffic…
9
113
15
577
41,022