XBOW

XBOW

@xbow.com

Bringing AI to offensive security by autonomously finding and exploiting web vulnerabilities. https://xbow.com/

463 followers9 following183 posts

How we chained three vulnerabilities into a full Chrome exploit in just 6 days—claiming Google’s first $250,000 full-chain reward of 2026 for an attack affecting an estimated 1 billion users. 🧵

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6/ Stage 3, The Renderer Refuses to Chill Out: Crashpad runs outside the renderer sandbox and trusted that a frozen process couldn't change. A Windows freeze-exempt thread flipped page protections mid-read—code exec in the unsandboxed crash handler. calc popped. 🧮

How we chained three vulnerabilities into a full Chrome exploit in just 6 days—claiming Google’s first $250,000 full-chain reward of 2026 for an attack affecting an estimated 1 billion users. 🧵

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4/ Stage 1, Mutating the Immutable: the vulnerable Maglev path made a mutable number look like exactly the sort of immutable constant the compiler was allowed to reuse—giving reliable memory access from JavaScript throughout the V8 sandbox.

5/ Stage 2, Two WebPs Diverged in a V8 Cage: we made a conscious decision to avoid attacking the sandbox itself. Both WebPs were valid on their own—the unsafe state existed only because Blink combined A's cached geometry with B's current bytes.

How we chained three vulnerabilities into a full Chrome exploit in just 6 days—claiming Google’s first $250,000 full-chain reward of 2026 for an attack affecting an estimated 1 billion users. 🧵

View full thread

2/ AI agents using OpenAI’s gpt-5.6-sol model searched source code, tested hypotheses, built proofs of concept, and developed exploit stages. Reconstructing usage from the archived Codex logs puts the six-day campaign at roughly $40,000 in API charges.

3/ The chain crossed two sandbox boundaries in three vulnerability stages: 1. Maglev reused a mutable boxed number during deoptimization 2. Animated WebP combined cached geometry with changed image bytes 3. Crashpad trusted a failed read from a supposedly frozen renderer

How we chained three vulnerabilities into a full Chrome exploit in just 6 days—claiming Google’s first $250,000 full-chain reward of 2026 for an attack affecting an estimated 1 billion users. 🧵

1/ Instead of asking one agent to produce an exploit end to end, we split the work into parallel campaigns: broad vulnerability search, V8 memory corruption, a V8 sandbox escape, a renderer sandbox escape, and integration.

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DMV Rising, which @virtru.bsky.social co-sponsors, is now Day 1 of DC's new Cyber Innovation Conference on Oct 26. On Day 2, startups pitch investors at the DataTribe Challenge. Good to see the region's security leaders and founders under one banner. dmvrising.com

dmvrising.comDMV RisingJoin us at DMV Rising and network with top cybersecurity and risk management professionals at our premier event, held in the heart of downtown Washington, D.C. Connect with industry leaders and expand your professional network in an exclusive setting.

Earlier this year, XBOW broke into the top 10 of the Microsoft Security Response Center(MSRC) leaderboard as the first and o nly AI in the ranking. Now we're finally able to disclose some of the coolest bugs we found.

TL;DR: Give an autonomous agent enough freedom and proper safeguards, and it will find an amazing zero-day without waking up your blue team.

Most security tools answer one question: what weaknesses exist here? They return a list, each item scored on its own. But attackers chain weaknesses. Finding these chains has historically required expensive human expertise. XBOW does this autonomously. Find out how: xbow.com/whitepapers/...

“Exploit proof” needs to rise to the top of your remediation program as a key modifier for findings, says Moderna Deputy CISO Farzan Karimi in a recent webinar with XBOW co-founder Nico Waisman. Hear more from Farzan below. Watch full webinar recording here: https://bit.ly/4eIForC

The Five Eyes cyber security agencies confirmed that AI-driven cyber risk is imminent. As the gap between discovery and exploitation shrinks, continuous, autonomous security testing becomes essential. That's the problem XBOW was built to solve. Read the full statement: https://bit.ly/4vsuzkh

How does XBOW identify business logic flaws? Hear from XBOW security researcher Alvaro Muñoz in the clip below. Get more of his thoughts on business logic flaws and how to address them in his new blog: https://bit.ly/4fKEpsP

In a new episode of the Cyberwire podcast, “Vulnerability response. Built for humans, outpaced by machines,” XBOW Head of Security Labs Federico Kirschbaum shares his perspective on vulnerability management when frontier models are finding the flaws. Listen to the episode: https://bit.ly/4epV5ov

AI Tinkerers is hosting an offensive security demo night on June 25 with XBOW. Live exploits, autonomous pentesting, LLM-assisted vulnerability discovery, code walkthroughs, and technical Q&A. No decks. No pitches. Working systems only. RSVP: https://bit.ly/3SdPtVS

Why are design flaws like IDOR so hard to find with automation? XBOW security researcher Alvaro Muñoz explains in the clip below. Get more of his thoughts on business logic flaws and how to address them in his new blog: https://bit.ly/4fKEpsP

If an organization can point a powerful language model at an application and unearth findings, is it effectively running a penetration test? Our new whitepaper breaks down where LLMs are powerful tools for pentesting, and where they need more support: https://bit.ly/4eqcEDH

We're honored that XBOW has been named a winner of Fast Company's 2026 World Changing Ideas Awards in the Business Products & Services category. This recognition reflects the work of our partners & research team, who believe the future of security is autonomous offense. More: https://bit.ly/4epnGca

Samsung SDS announced that it is partnering with XBOW to strengthen its cybersecurity capabilities, using XBOW to uncover hidden vulnerabilities through attack simulations and accelerate identification and remediation with unmatched speed and precision. Get details: https://bit.ly/4oo3zjs

“AI is changing the story of design flaw identification, says XBOW security researcher Alvaro Muñoz in the clip below. Get more of his thoughts on business logic flaws and how to address them in his new blog: https://bit.ly/4fKEpsP

Great spending time with the GuidePoint Security team and customers this week at the GuidePoint Security Golf Classic at Terry Hills. As attack surfaces grow and vulnerabilities multiply, strong partnerships matter. Together, we're helping organizations validate real, exploitable risk.

How does AI pentesting work? What should you look for? Get some guidance in our blog post "How to Evaluate an AI Pentesting Vendor: A Decision Framework for Security Leaders." https://bit.ly/4edHyPM

• Why can't traditional pentests keep up with modern attack surfaces? • What stops an autonomous pentesting agent from causing real damage in production? Our CISO answers these questions and more on the Security You Should Know podcast. Listen to the full episode: https://bit.ly/4eiMXWM

Moderna Deputy CISO Farzan Karimi shared how XBOW uncovered attack paths human testers missed, including one that took down a development environment during a trial. This @cyberscoop.bsky.social piece examines what happens when offensive security moves at machine speed: https://bit.ly/4va5Pxr

One theme came up repeatedly at InfoSecurity Europe: ➡️ Security teams want proof, not possibility. Great discussions all week with leaders thinking about autonomous offensive security and operational validation at scale. Thanks to everyone who connected with our team.

On June 10, XBOW CISO Nico Waisman and Moderna Deputy CISO Farzan Karimi will discuss the impact of autonomous, continuous, and exploit-validated offensive security in today’s AI threat landscape. Join us: https://bit.ly/42zUvxV

GPT-5.5 is now part of XBOW. In our testing, GPT-5.5 delivered major gains in vulnerability discovery, exploit reasoning, application interaction, and autonomous testing. Models provide the intelligence. XBOW turns it into autonomous application security. Read more: https://bit.ly/4ufvhAb

Thank you to everyone who joined yesterday's #GartnerSEC session with Farzan Karimi and Troy West of Moderna to learn how they're building an autonomous offensive security program with XBOW! It’s day two, and we’re ready to talk all things autonomous offensive security. Find us at booth 1028!

Today at #Infosec2026, attendees will get a chance to put offensive security to the test during our workshop: Offensive AI in Practice. See firsthand how AI amplifies attackers’ abilities and how offensive security tools find, exploit, validate, and remediate them. Register: https://bit.ly/4d9cd19

Our team is at #Infosec2026 today through Thursday! Stop by booth F-135 to say hi to the team 👋 and learn how your organization can scale offensive security with XBOW. 🏹 https://bit.ly/3P1Vkwj

If you’re at Gartner Security & Risk Management Summit today, find the XBOW team at booth 1028 📍 to learn about autonomous offensive security and how it’s enabling teams to defend against complex and evolving cyberthreats faster, better, and at scale: https://gtnr.it/2Mf36ll #GartnerSEC

Attending Gartner Security & Risk Management Summit? Tune in as Moderna’s Farzan Karimi and Troy West take the stage to share how XBOW enables them to meet the demands of today’s AI-driven cybersecurity landscape. 🔔 TODAY at 02:05 PM EDT: https://gtnr.it/4nQofA6 #GartnerSEC

On June 16 at 11AM EDT, XBOW Lead Solutions Architect Bill Reyor will break down why security leaders are moving beyond periodic assessments toward continuous offensive security testing. If your exposure changes daily, your testing strategy should too. Register at the link: https://bit.ly/42Nm472

Meet XBOW at the Gartner Security & Risk Management Summit next week at Booth 1028! 📍 Plus, don't miss Moderna’s session where Farzan Karimi and Troy West will discuss how they’re working with XBOW to dramatically increase the speed, scale, and continuity of testing: https://gtnr.it/4nQofA6

The Future of Pen Testing Is Continuous Security Testing Gartner® research on why point-in-time testing can no longer keep pace and what security leaders are doing instead. Download the report now: https://bit.ly/4dpavZF

In less than two weeks at Infosecurity Europe 2026, XBOW will lead a hands-on workshop: Offensive AI in Practice. 📍 June 2nd, 2pm BST South Gallery Room 18 @ ExCeL London Secure your spot: https://bit.ly/4d9cd19