Deserialization in Langchain Core
CVE-2025-68664
LangChain is a framework for building agents and LLM-powered applications. Prior to versions 0.3.81 and 1.2.5, a serialization injection vulnerability exists in LangChain's dumps() and dumpd() functions. The functions do not escape dictionaries with 'lc' keys when serializing free-form dictionaries. 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 versions 0.3.81 and 1.2.5.
Vulnerability class: Insecure Deserialization
Published · last modified .
CVSS v3 metric
CVSS v3 base score 9.3 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:L/A:N.
EPSS exploit prediction
EPSS: 0.429 (98.7th percentile), scored .
Moderate probability of exploitation in the next 30 days — watch for active exploitation reports. 99th percentile — 98.7% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.434 · newest: 0.429 · change: -0.005
Affected products
- Langchain Core
- Langchain-Ai Langchain — versions >= 1.0.0, < 1.2.5, < 0.3.81
Weakness classification (CWE)
Public proof-of-concept exploits
References
- github.com/langchain-ai/langchain/security/advisories/GHSA-c67j-w6g6-q2cm (Exploit, Vendor Advisory)
- github.com/langchain-ai/langchain/pull/34455 (Patch, Issue Tracking)
- github.com/langchain-ai/langchain/pull/34458 (Patch, Issue Tracking)
- github.com/langchain-ai/langchain/commit/5ec0fa69de31bbe3d76e4cf9cd65a6accb8466… (Patch)
- github.com/langchain-ai/langchain/commit/d9ec4c5cc78960abd37da79b0250f5642e6f0c… (Patch)
- github.com/langchain-ai/langchain/releases/tag/langchain-core==0.3.81 (Release Notes)
- github.com/langchain-ai/langchain/releases/tag/langchain-core==1.2.5 (Release Notes)
Frequently asked questions
- What is CVE-2025-68664?
- CVE-2025-68664 is a critical-severity vulnerability in Langchain Core, classified under Deserialization of Untrusted Data. CVSS score: 9.3/10. Published 2025-12-23.
- How severe is CVE-2025-68664?
- Critical severity. CVSS v3 base score is 9.3 out of 10.
- Is CVE-2025-68664 known to be exploited?
- 3 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.