LangChain is a framework for building agents and LLM-powered applications. From versions 0.3.79 and prior and 1.0.0 to 1.0.6, a template injection vulnerability exists in LangChain's prompt template system that allows attackers to access Python object internals through template syntax. This vulnerability affects applications that accept untrusted template strings (not just template variables) in ChatPromptTemplate and related prompt template classes. This issue has been patched in versions 0.3.80 and 1.0.7.
https://github.com/langchain-ai/langchain/security/advisories/GHSA-6qv9-48xg-fc7f
https://github.com/langchain-ai/langchain/commit/fa7789d6c21222b85211755d822ef698d3b34e00
https://github.com/langchain-ai/langchain/commit/c4b6ba254e1a49ed91f2e268e6484011c540542a
Published: 2025-11-21
Updated: 2026-04-15
Base Score: 7.5
Vector: CVSS2#AV:N/AC:L/Au:N/C:P/I:P/A:P
Severity: High
Base Score: 9.8
Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Severity: Critical
Base Score: 8.3
Vector: CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:L/VA:N/SC:N/SI:N/SA:N
Severity: High
EPSS: 0.00045