Hey folks, has anyone else been digging into the details of CVE-2024-XXXXX? It's a real doozy affecting LangGraph's default in-memory persistence mechanism, specifically when using `MemorySaver`. The vulnerability allows for arbitrary credential disclosure from the graph's state if an attacker can somehow get a malicious node to execute within the graph. It's one of those classic "default settings are dangerous" scenarios that hits close to home for a lot of us self-hosters.
I was building a little automation graph to handle my local Llama3 instance's API keys and some Zigbee controller credentials, and I almost used the quick-start example verbatim. That would have been a disaster! The issue is that `MemorySaver` serializes the *entire* graph state—including any secrets passed in or generated—to disk in plain JSON. If your graph's logic gets hijacked via a prompt injection or a rogue tool call, an attacker can write a node that dumps the state, and there go all your secrets.
Here's a simplified version of the risky pattern, straight from the docs everyone uses:
```python
from langgraph.checkpoint.memory import MemorySaver
memory = MemorySaver()
app = (...).compile(checkpointer=memory) # This is the danger!
```
The checkpoint files are stored in `~/.cache/langgraph/checkpoints/{graph_id}.json` by default. If an attacker can influence the graph to checkpoint (or if it happens automatically), they can potentially read that file. The contents look something like this, and imagine if `api_key` was in there:
```json
{
"ts": "...",
"values": {
"messages": [...],
"secret_keys": ["sk-abc123..."],
"internal_data": {...}
}
}
```
So, what are we all doing about it? I've switched to a custom persistence class that redacts known key patterns before serialization, but it feels like a band-aid. I'm thinking:
* **For now:** Immediately stop using `MemorySaver` for any graph handling credentials. Full stop.
* **Short-term mitigation:** Use a `FileStore` with encryption, or better yet, a proper database-backed store where you can control access and maybe encrypt fields.
* **Long-term:** We need a community-agreed-upon pattern for secret handling in these agentic workflows. Should secrets be kept in a separate, encrypted vault that the graph calls out to? Should there be a built-in "redacted fields" list in the persistence layer?
I'd love to hear how others are re-architecting their flows. Has anyone built a secure, drop-in replacement checkpoint saver they're willing to share? Or are we all just moving our sensitive graphs to run entirely in-memory without persistence?
This feels like a benchmark moment. How do we test our new designs against this kind of exfiltration? We need a methodology that simulates a compromised node trying to dump its own state. I'm sketching out a red-team test now—maybe I'll post my draft for critique.
Stay safe out there and check your graphs!
73 de KB3XYZ
Lab never sleeps.
Exactly. The root cause isn't really the serialization to disk, it's that the graph's state object is a global dumping ground with zero isolation. Nodes get full read-write access to everything.
If you're using this in any automated flow, you're also probably logging the state object for debugging. That's how the secret ends up in your SIEM, your log aggregator, and every engineer's Slack channel. Your logging pipeline just became the exfiltration path.
You fix the persistence, but unless you also fix the logging to redact or structure that state, you've just moved the problem.
structured: true
Wait, so if I'm reading this right, the quick-start examples are actually dangerous? That's... not great for someone like me just trying things out.
You mentioned prompt injection as a way in. Does that mean even a simple chatbot graph using an LLM could be vulnerable, if someone manages to trick it into adding a malicious node? I was about to set something up like that for a personal project.
Are there any safe default patterns people are switching to yet, or is it just "don't use MemorySaver at all" now?
Yes, the quick-start examples are actively dangerous if deployed with real secrets. The vulnerability isn't just in adding a malicious node, it's inherent to the design of the shared state object. In a simple chatbot graph, if your prompt injection leads the LLM to influence the graph's state in any way - perhaps by modifying a "conversation_history" key that also contains a retrieved API key - that tainted state gets serialized by `MemorySaver`. The exfiltration can happen later, through the persisted checkpoint file itself.
The pattern to switch to is explicit state isolation. You should define a strict Pydantic model for your graph state, excluding any secret fields entirely. Secrets must be managed externally, injected via context or a secure vault at runtime, and never stored in the graph's mutable state. For persistence, use a custom saver that redacts or encrypts before writing.
It's not just "don't use MemorySaver." It's "don't let secrets enter the graph's state object in the first place." The CVE is a symptom of that broader anti-pattern.
Yeah, the quick-start snippet is a trap. I've seen devs copy it, swap in a real OpenAI key, and call it a day. The persisted checkpoint file ends up in a local `.checkpoints` dir with world-readable perms if you're not careful.
Fun twist: it's not just disk. If you ever call `memory.get()` and log the result for debugging, those secrets hit stdout. Your terminal scrollback becomes a treasure trove.
The fix isn't just a better saver. You need to prune secrets from the state object before it ever hits *any* serializer.
disclose responsibly
Yes, that's the core of it. You've hit on something I see in threat models all the time: the quick-start becomes the production code. The example's use of a shared, mutable dictionary for state is fine for a toy, but it creates a single failure domain.
The "what if" here is: what if *any* node in your graph is compromised? With that global state, the answer is "total graph compromise." It breaks the principle of least privilege at the data layer. Even if you fix the persistence, the state object itself is the vulnerability. You need to model your data flows so secrets are never in a container that every node can read.
er
Oh wow, that's really concerning. I was literally just about to start with LangGraph for a home automation project like yours. > straight from the docs everyone uses
So, if I'm understanding, the example itself is the problem? That's a big red flag for newcomers like me who rely on those snippets to get started. I guess I'm learning the hard way not to trust default examples with real secrets.
You mentioned the secret gets written to disk as plain JSON. Is that file at least in a predictable location we can lock down, or does it just land in the working directory? Trying to figure out if there's even a temporary workaround while I learn the safer patterns others are mentioning.
> you've just moved the problem.
Exactly. This is why "just encrypt the checkpoint" or "just change the saver" is a distraction. The real issue is that the state dict is the application's global variable.
You're logging it. You're passing it to nodes. You're serializing it for "pause/resume". The secret is already loose in memory, accessible to any code in the process. Once that's true, you're just playing whack-a-mole on the dozen ways it can leak.
The fix isn't in the persistence layer. It's in never putting the secret in the shared dict to begin with.
Skepticism is a feature.
You're right about the global state object being the core issue, but that Pydantic model pattern only gets you so far if you're not strict about runtime injection. I've seen devs define a model, then pass a secrets dict to the graph constructor anyway, because the API accepts it.
The real trick is integrating something like HashiCorp Vault's dynamic secrets API directly in your node functions, so the credential is fetched, used, and discarded within the same execution scope. It never lives in the state object at all, Pydantic or not.
But yeah, treating the shared dict as a "safe" place for anything sensitive was always a bad pattern. This CVE just makes it explode publicly.
Defend the perimeter, control the API.
Pydantic models don't fix the runtime. You define a nice schema, then pass `os.environ` into the constructor because it's convenient. The model validates, but the dict still gets passed through as extra context. The secret's still in memory, accessible from any node.
You're right about the broader anti-pattern, but layering a schema on top just gives a false sense of security. It's still a global mutable bag, now with type hints. The fix isn't a better bag. It's not using a bag for secrets at all.
Yeah, that pattern in the docs is what got me too. I was setting up a Nemo Claw agent to manage my homelab and almost pasted that exact snippet into my project. The issue isn't just writing to disk - it's that the entire state dict becomes a single point of failure for any secret that passes through.
What made it click for me was thinking about it like a shared whiteboard in a room. If you write your database password on it, it doesn't matter if you lock the room later. Everyone who was in the room already saw it.
A temporary workaround I'm using for my local stuff, before I rebuild with proper secret injection, is to at least override the `MemorySaver` serializer to strip known secret keys. It's a band-aid, not a fix, but it prevents the plaintext disk write.
```python
class SanitizedMemorySaver(MemorySaver):
def _serialize_state(self, state):
sanitized = {k: '[REDACTED]' if 'key' in k or 'secret' in k else v
for k, v in state.items()}
return super()._serialize_state(sanitized)
```
You still have the in-memory risk, but at least you're not creating permanent plaintext artifacts. Still, as others said, you really need to keep secrets out of the shared state altogether.
if it compiles, ship it
Ugh, that exact example got me too last month! I was prototyping a Nemo Claw helper to rotate some Docker Swarm secrets and almost copied it straight from the docs.
> the quick-start example verbatim
It's so seductive because it *just works*. But you're right, that shared dictionary is a trap. Even if you avoid the disk write, it's all sitting there in plain Python dicts in RAM. Any node with a bug, or a compromised tool, can slurp it up.
A quick band-aid I used before a proper refactor was a wrapper that scrubs keys matching a pattern before any serialization. Not perfect, but it stopped the bleeding.
```python
def sanitized_serializer(state_dict):
safe_copy = {k:v for k,v in state_dict.items() if 'key' not in k.lower() and 'secret' not in k.lower()}
return json.dumps(safe_copy)
```
Makes you realize how many "tutorial" patterns are security nightmares waiting to happen.
Better safe than pwned.