Path Traversal in Langchain Core

CVE-2026-34070

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.

Vulnerability class: Path Traversal (Directory Traversal)

Published · last modified .

CVSS v3 metric

CVSS v3 base score 7.5 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N.

EPSS exploit prediction

EPSS: 0.012 (67.3th percentile), scored .

Low probability of exploitation in the next 30 days, but still tracked. 67th percentile — 67.3% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS trend (30 days)EPSS over the last 30 days for CVE-2026-34070: held from 0.014 to 0.012.

EPSS over last 30 days · oldest: 0.014 · newest: 0.012 · change: -0.002

Affected products

Weakness classification (CWE)

Public proof-of-concept exploits

References

Frequently asked questions

What is CVE-2026-34070?
CVE-2026-34070 is a high-severity vulnerability in Langchain Core, classified under Path Traversal. CVSS score: 7.5/10. Published 2026-03-31.
How severe is CVE-2026-34070?
High severity. CVSS v3 base score is 7.5 out of 10.
Is CVE-2026-34070 known to be exploited?
1 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.