Is It CitrixBleed4? Well, No. Is It Good? Also, No. (Citrix NetScaler Memory Leak & RXSS CVE-2025-12101)

Is It CitrixBleed4? Well, No. Is It Good? Also, No. (Citrix NetScaler Memory Leak & RXSS CVE-2025-12101)

By @sinsinology
Publication Date: 2025-11-12 13:03:00

There’s an elegance to vulnerability research that feels almost poetic – the quiet dance between chaos and control. It’s the art of peeling back the layers of complexity, not to destroy but to understand; to trace the fragile threads that hold systems together and see where they might fray.

There’s beauty in that tension – the simultaneous act of breaking and creating, of exposing weakness to make strength possible. It’s a kind of intellectual intimacy, where curiosity meets consequence, and discovery hums just beneath the surface of what others take for granted.

And sometimes, you casually click your way to a vulnerability with a web browser.

Yes! We are discussing security appliances today!

As we’ve discussed before, it’s not uncommon to stumble into zero-days while exploring a code base or system in the pursuit of reproducing an N-day.

CitrixBleed2

That’s exactly what happened in August 2025, when we triggered a rapid-response event across our client base for…