CVE-2026-34070

HIGH

LangChain Core has Path Traversal vulnerabilites in legacy `load_prompt` functions

Title source: cna
STIX 2.1

Exploitation Summary

EIP tracks 1 public exploit for CVE-2026-34070. PoCs published by Rickidevs.

AI-analyzed exploit summary This is a detailed technical writeup discussing CVE-2026-34070, a path traversal vulnerability in LangChain's `langchain-core` library. It includes root cause analysis, proof-of-concept examples, and mitigation steps.

Description

LangChain is a framework for building agents and LLM-powered applications. Prior to version 1.2.22, multiple functions in langchain_core.prompts.loading read files from paths embedded in deserialized config dicts without validating against directory traversal or absolute path injection. When an application passes user-influenced prompt configurations to load_prompt() or load_prompt_from_config(), an attacker can read arbitrary files on the host filesystem, constrained only by file-extension checks (.txt for templates, .json/.yaml for examples). This issue has been patched in version 1.2.22.

Exploits (1)

nomisec WRITEUP
by Rickidevs · poc
https://github.com/Rickidevs/CVE-2026-34070

This is a detailed technical writeup discussing CVE-2026-34070, a path traversal vulnerability in LangChain's `langchain-core` library. It includes root cause analysis, proof-of-concept examples, and mitigation steps.

Classification
Writeup 100%
Attack Type
Info Leak
Complexity
Trivial
Reliability
Reliable
Target: langchain-core < 1.2.22
No auth needed
Prerequisites: ability to influence config dict passed to `load_prompt()` or `load_prompt_from_config()`
devstral-2 · analyzed Apr 28, 2026 Full analysis →

References (3)

Core 3

Scores

CVSS v3 7.5
EPSS 0.0004
EPSS Percentile 11.5%
Attack Vector NETWORK
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N

CISA SSVC

Vulnrichment
Exploitation poc
Automatable yes
Technical Impact partial

Details

CWE
CWE-22
Status published
Products (4)
langchain/langchain < 1.2.22
langchain/langchain_core < 1.2.22
langchain-ai/langchain < 1.2.22
pypi/langchain-core 0 - 1.2.22PyPI
Published Mar 31, 2026
Tracked Since Mar 31, 2026