How severe is CVE-2026-34070?

CVE-2026-34070 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity none, and availability none.

Is CVE-2026-34070 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (64th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2026-34070?

CVE-2026-34070 affects Langchain Langchain Core. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2026-34070?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.

Does CVE-2026-34070 have an EU (EUVD) identifier?

Yes. CVE-2026-34070 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-17283.

When was CVE-2026-34070 published?

CVE-2026-34070 was published on 2026-03-31 and last updated on 2026-06-30.

CVE-2026-34070

CVE-2026-34070 is a high-severity vulnerability in Langchain Langchain Core with a CVSS 3.x base score of 7.5. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-22.

Key facts

Severity: High (CVSS 3.x base score 7.5)
EPSS exploit prediction: 1% (64th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2026-17283
Weakness: CWE-22
Affected product: Langchain Langchain Core
Published: 2026-03-31
Last modified: 2026-06-30

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.

Frequently asked questions

What is 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.
How severe is CVE-2026-34070?: CVE-2026-34070 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity none, and availability none.
Is CVE-2026-34070 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (64th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-34070?: CVE-2026-34070 affects Langchain Langchain Core. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2026-34070?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
Does CVE-2026-34070 have an EU (EUVD) identifier?: Yes. CVE-2026-34070 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-17283.
When was CVE-2026-34070 published?: CVE-2026-34070 was published on 2026-03-31 and last updated on 2026-06-30.

References

Affected products (1)

cpe:2.3:a:langchain:langchain_core:*:*:*:*:*:python:*:*

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