Improper Neutralization of Special Elements Used in a Template Engine Affecting langchain-core package, versions [,0.3.84)[0.4.0.dev0, 1.2.28)
Threat Intelligence
The probability is the direct output of the EPSS model, and conveys an overall sense of the threat of exploitation in the wild. The percentile measures the EPSS probability relative to all known EPSS scores. Note: This data is updated daily, relying on the latest available EPSS model version. Check out the EPSS documentation for more details.
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Test your applications- Snyk IDSNYK-PYTHON-LANGCHAINCORE-15953340
- published9 Apr 2026
- disclosed8 Apr 2026
- creditUnknown
Introduced: 8 Apr 2026
CVE-2026-40087 (opens in a new tab)How to fix?
Upgrade langchain-core to version 0.3.84, 1.2.28 or higher.
Overview
langchain-core is a Building applications with LLMs through composability
Affected versions of this package are vulnerable to Improper Neutralization of Special Elements Used in a Template Engine via the template formatting. An attacker can access internal object fields or nested data by supplying specially crafted template strings that include attribute access or indexing expressions, which are evaluated during formatting.