CVE-2025-68665 is a high-severity (CVSS 8.6) Deserialization of Untrusted Data vulnerability in @langchain/core. A fix is available for @langchain/core — see the affected versions and patch details below.
LangChain serialization injection vulnerability enables secret extraction
Exploitation Status
Proof-of-concept exploit code exists
- CISA’s SSVC triage found public proof-of-concept exploit code for this CVE, though no confirmed active exploitation.
- CISA assesses this as automatable — exploitation doesn’t require manual, per-target effort, which raises the odds of mass scanning and opportunistic attacks.
Exploitation and automatability from CISA’s SSVC triage for CVE-2025-68665.
EPSS Exploitation Probability
EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.
How urgent is this, really
CVE-2025-68665 plotted by exploitation likelihood (EPSS) against impact (CVSS). The shaded corner — EPSS 50%+ and CVSS 7.0+ — is where this CVE doesn't sit, though severity or exploitability alone can still warrant action.
Where this sits among everything scored
Of 377,333 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Real counts from FIRST.org, not a sample — log-scaled since the landscape is heavily right-skewed.
Real-World Exposure
How broadly this vulnerability is actually deployed: weekly install volume shows current usage, and reverse-dependency count shows how many other packages break if it stays unpatched.
@langchain/corenpmlangchainnpmDescription
LangChain is a framework for building LLM-powered applications. Prior to @langchain/core versions 0.3.80 and 1.1.8, and prior to langchain versions 0.3.37 and 1.2.3, a serialization injection vulnerability exists in LangChain JS's toJSON() method (and subsequently when string-ifying objects using JSON.stringify(). The method did not escape objects with 'lc' keys when serializing free-form data in kwargs. The 'lc' key is used internally by LangChain to mark serialized objects. When user-controlled data contains this key structure, it is treated as a legitimate LangChain object during deserialization rather than plain user data. This issue has been patched in @langchain/core versions 0.3.80 and 1.1.8, and langchain versions 0.3.37 and 1.2.3
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 📦npm | @langchain/core | ≥ 1.0.0&&< 1.1.8 | 1.1.8npm install @langchain/core@1.1.8 |
| 📦npm | @langchain/core | all versions | 0.3.80npm install @langchain/core@0.3.80 |
| 📦npm | langchain | ≥ 1.0.0&&< 1.2.3 | 1.2.3npm install langchain@1.2.3 |
| 📦npm | langchain | all versions | 0.3.37npm install langchain@0.3.37 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for @langchain/core, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update @langchain/core to 1.1.8 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2025-68665 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like CVE-2025-68665 can be triaged on real exposure rather than presence alone.
Tailored to CVE-2025-68665. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Fixing This On Your OS
If you run this on a Linux distribution, patch through your package manager against the distro's own security advisory below — it tracks the exact backported fix for your release, which can ship on a different timeline (and sometimes a different severity) than the upstream project.
This vulnerability is rated Important for Red Hat products. A serialization injection flaw in LangChain's `toJSON()` method allows a remote attacker to achieve arbitrary code execution. This occurs when user-controlled data containing specific 'lc' key structures is improperly processed as a legitimate LangChain…
| Product | Fixed in | Advisory |
|---|---|---|
| Red Hat OpenShift AI 3.3 | rhoai/odh-llama-stack-core-rhel9:1771415661 | RHSA-2026:3713 |
Frequently Asked Questions
Is CVE-2025-68665 in your dependencies?
O3 Security finds CVE-2025-68665 across npm dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.