shahartal

Author here (Yarden & Shahar from Check Point Research). Context on what this is and isn't:

We set out to break Cloudflare's Code Mode and ended up in workerd, the runtime underneath both Code Mode and Cloudflare Workers. Five memory-corruption bugs in workerd's native C++ "glue" (the layer that hands C++ objects to untrusted JS), two rated Critical by Cloudflare. We chained them into two end-to-end attacks: a cross-tenant heap read that swipes another Worker's secrets, and a Code Mode sandbox escape that goes from a single prompt injection to native code on the host.

The core insight: the V8 "cage" and memory-protection keys don't cover the tcmalloc native heap - and that's exactly where the glue layer allocates its objects. If the cage is your isolation story, the memory it doesn't cover is your attack surface.

Honest caveats: both full exploits were verified on self-hosted workerd, not run against Cloudflare production. The cross-tenant path should behave the same in prod since it runs entirely on the uncovered tcmalloc heap, but we didn't test it there. Cloudflare has fixed managed Workers in production; self-hosted deployments should update to workerd v1.20260619.1. No CVEs assigned or advisories issued by Cloudflare policy.

Happy to answer questions.

CVE-2025-68664 (langchain-core): object confusion during (de)serialization can leak secrets (and in some cases escalate further). Details and mitigations in the post.

Hey all — authors of Vault Fault here (I’m Shahar, CEO at Cyata), really appreciate all the thoughtful comments.

Just to clarify - all the vulnerabilities were found manually by a very real human, Yarden Porat.

The writeup was mostly human-written as well, just aimed at a broader audience - which explains the verbosity. We did work with a content writer to help shape the structure and flow, and I totally get that some parts read a bit “sheeny.” Feedback noted and appreciated - and yep, there’s more coming :)

btw likely missed with the direct link - we also found pre-auth RCE in CyberArk Conjur - cyata.ai/vault-fault

all fighter jet principals and employees should have arrest warrants out for them. those damn fighter jets makers, killing people around the world with their jets. I mean, what did they think they are making a fighter jet for, they chose to work there and should have known the risks of being in the jet fighter business.

fixed. anyone else experiencing trouble?