Security Digest · Vulnerability record
CVE-2025-68665: LangChain serialization injection vulnerability enables secret extraction
LangChain is a framework for building LLM-powered applications.
CVSS 8.6 High EPSS 0.8% · p56 Patch this week
Should you act?
Normal patch cycle
No exploitation signal; fix it in your next routine update if you are affected. This signal is computed from CISA KEV, EPSS and CVSS data; it is not an editorial verdict.
- Not in CISA KEV, but CISA’s SSVC assessment records a public proof-of-concept, so attack code exists.
- EPSS 0.8%, percentile 56: FIRST’s model estimates a 0.8% chance of exploitation activity in the next 30 days, higher than 56% of all scored CVEs (moderate). EPSS is a probability, not a verdict.
- Remotely reachable with no login and no user interaction. If the vulnerable service is exposed to the internet, prioritize it.
- Editorial verdict: Patch this week. LangGrinch: LangChain Core Serialization Injection — A real design flaw in a library almost every Python agent stack pulls in, but it needs a serialize-then-deserialize path over attacker-influenced data; bump langchain-core in your next routine dependency update.
What it is
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
Weakness type: CWE-502.
Product: langchain-ai langchainjs · Assigned by: GitHub_M · Published: 2025-12-23
Affected and fixed versions
| Vendor | Product | Affected versions (per CVE record) |
|---|---|---|
| langchain-ai | langchainjs | @langchain/core >= 1.0.0, < 1.1.8, @langchain/core < 0.3.80, langchain >= 1.0.0, < 1.2.3, langchain < 0.3.37 |
Severity scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| GitHub_M | 3.1 | 8.6 High | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:N/A:N |
- Attack vector: network (remotely reachable)
- Attack complexity: low
- Privileges required: none (no login)
- User interaction: none
- Scope: changed (can affect other components)
CVSS measures how bad a flaw is if exploited, not how likely exploitation is. Read it next to the exploitation data below.
Exploitation and urgency
- CISA KEV: not listed (no confirmed in-the-wild exploitation known to CISA).
- CISA SSVC assessment: exploitation poc, automatable yes, technical impact partial.
- FIRST EPSS (model of 2026-10-21): 0.79% probability of exploitation activity in the next 30 days; percentile 56.
Timeline
- — CVE record published by GitHub_M
- — erroneo.us brief: LangGrinch: LangChain Core Serialization Injection
- — CVE record last updated
Sources and references
Original sources first. Version and fix details should always be confirmed against the vendor or project advisory.
Vulnerability records
- CVE.org record CVE-2025-68665 cve.org
- NVD entry CVE-2025-68665 nvd.nist.gov
Other references from the CVE record and advisory
- github.com github.com
- github.com github.com
- github.com github.com
- github.com github.com