p2jb-y2jb

PlayStation 5 jailbreak (firmware 9.00 – 12.40) — a port of Gezine / cheburek3000's p2jb kernel exploit (cr_ref overflow via kqueueex) from the luac0re (lua-loader) host to Y2JB (YouTube / V8 JavaScript host).

Confirmed working: jailbreak end-to-end + GPU-DMA debug menu + ELF loader (delivered automatically by the Y2JB host) + persistent unpatcher delivery. Closing the YouTube host app after completion no longer kernel-panics the console.

Firmware support: works on 9.00 – 12.40.

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How it works

The payload triggers a 32-bit cr_ref overflow in the PS5 kernel (via ~2³² kqueueex syscalls, ~50 minutes), uses the resulting use-after-free to build a kernel read/write primitive, escalates the host process to root, enables the Debug Settings menu via GPU DMA writes on the read-only kernel .data segment, then delivers an ELF loader inside the YouTube process. The binary and delivery mechanism depend on the installed Y2JB version (see PS5 setup (Y2JB) below). Either way the loader ends up listening on TCP :9021 for ELFs to run on the jailbroken PS5.

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Requirements

PS5 setup (Y2JB)

This payload runs inside the Y2JB userland framework on the PS5 (the YouTube TV app modded to run arbitrary JavaScript). Before you can send anything to the console, you must restore Gezine's Y2JB system backup on the PS5 — see Gezine/Y2JB for the backup file and the restore procedure. Without Y2JB restored and the YouTube TV app launched, the PS5 has no listener for the payload and nothing will happen.

Y2JB 1.3 or newer. The ELF loader is delivered differently depending on Y2JB version. The payload detects the framework version at runtime (from Y2JB's version_string global) and picks the matching path automatically — you don't need to configure anything.

• Y2JB 1.5+: the payload hands off to Y2JB's bundled kexp shellcode (load_aioshellcode), which loads elfldr-ps5-0.23.elf from inside the framework. No USB, nothing to provide.
• Y2JB 1.4: the payload reads elfldr_1320_v5.elf directly from the Y2JB sandbox slot — no USB needed.
• Y2JB 1.3: Y2JB 1.3 bundles an outdated elfldr.elf that does not work on the current kernels, so the payload reads elfldr_1320.elf from a USB stick plugged into the PS5 (/mnt/usb0 ... /mnt/usb7). Grab elfldr_1320_v5.elf from this repo, put it on the root of a FAT32/exFAT USB (you can rename it to elfldr_1320.elf or elfldr.elf if you prefer — all three are probed), and plug the USB in before launching the payload.

At the very start the payload checks the framework helpers it needs are in scope: if anything is missing it aborts before touching the kernel (no leak, no stage 0).

Hardware

• PlayStation 5 console running firmware 9.00 – 12.40.
• A PC on the same LAN as the PS5.
• (Y2JB 1.3 only) A FAT32/exFAT USB stick with elfldr_1320.elf on its root. On Y2JB 1.4+ no USB is needed.

Software (on PC)

• The payload_sender.py delivery tool from Gezine/Y2JB (not included here).
• Al-Azif/hermes-link (or any equivalent tool) for delivering ELFs to the loader on :9021.

Files

• p2jb.js — the jailbreak payload (this repo).
• elfldr_1320_v5.elf — Gezine's ELF loader binary, included here for Y2JB 1.3 users who need to provide it via USB. Y2JB 1.4 bundles the same file inside the framework; Y2JB 1.5+ ships its own bundled elfldr-ps5-0.23.elf instead. In either of those two cases you can ignore this file.

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Usage

1. Send the payload

From the PC:

python payload_sender.py <ps5-ip> p2jb.js

The payload streams its log back to payload_sender.py's console.

2. Wait ~50 minutes

The cr_ref leak dominates the runtime. The payload sender will stay silent for the whole leak — no per-percentage progress is printed. Don't assume it has crashed; the worker is internally checked for liveness and a stall would surface as a FATAL log line. Do not interact with the PS5 while it runs.

3. Look for completion

[p2jb] stage_elfldr: elfldr launched - listening on :9021
[p2jb] === p2jb complete ===

At this point you have an in-memory jailbreak and a generic ELF loader. Any ELF you send to :9021 will run on the jailbroken PS5.

Sending an ELF to :9021

A convenient tool for delivering ELFs to the loader is Al-Azif/hermes-link. It takes care of the TCP handshake the loader expects, so you don't have to write the byte protocol yourself.

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Tuning: leak speed vs. stability

The cr_ref leak runs across multiple pinned worker threads in parallel. The default is 4 cores (cores 0–3; core 4 stays free for the orchestrator):

// p2jb.js
const LEAK_CORES = [0, 1, 2, 3];   // ~48 min, default

On hardware that's unstable at 4 cores (kernel panics during the leak phase, or runs that never reach Stage 0), dropping to fewer cores trades wall-clock time for stability — fewer parallel workers means less contention on the kernel kqueueex allocator and a markedly higher chance of completing.

To change it: open p2jb.js, search for LEAK_CORES, edit the array, save the file, and run payload_sender.py as usual. Try the default first; only fall back to fewer cores if you see kernel panics during the leak or if Stage 0 doesn't appear after well over an hour.

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Known limitations

• One run per boot. A p2jb.fail marker is dropped at stage 0 entry to refuse re-runs without a reboot — the triple-free is a point of no return.
• The ELF loader lives inside the YouTube process. Closing the app is safe for the kernel, but it tears down the loader and any ELF you sent to :9021. Keep YouTube open until your persistent payload (e.g. BD-UN-JB) has applied; afterwards you can close the app normally.

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A note from the author

I don't normally work on PS5 exploits or low-level reverse engineering. This repository is the result of a personal attempt to understand how the scene's techniques work — not a contribution from a scene developer. I'm publishing it in case it's useful to someone on firmware 11.60 who is stuck, but please don't read it as me claiming expertise on the topic. The real work is by the people credited below; I just tried to glue their primitives into a working flow on the Y2JB host and learn along the way.

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Credits

• p2jb kernel exploit (cr_ref overflow via kqueueex) — Gezine / cheburek3000. Luac0re.
• netcontrol kernel exploit (original) — TheFlow. Source of the kqueue leak and UIO/IOV R/W primitives reused here.
• Y2JB userland framework — Gezine. Y2JB.
• kexp post-jailbreak all-in-one shellcode — ufm42 (kexp), merged into Y2JB 1.4.
• remote_lua_loader p2jb port — notmaj0r. Used as a secondary reference during the port.
• lapse (Y2JB) — referenced for the gpu.js debug-menu apply flow; not the exploit itself (lapse exploits AIO, not kqueueex).
• Edigax — help with the multi-core leak implementation, bringing the cr_ref leak down from ~2 hours to ~48 minutes.
• Rviju and Dr.Yenyen — help running test builds on real hardware during the close-KP investigation.
• Claude (Anthropic) — AI assistant used throughout the port.

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License

MIT — see LICENSE.