Deserialization of Untrusted Data Affecting langchain-core package, versions [,0.3.85)[1.0.0a1,1.3.3)
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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- published10 May 2026
- disclosed8 May 2026
- creditu-ktdi, pucagit, Moaaz-0x, shrutilohani, dewankpant
Introduced: 8 May 2026
CVE-2026-44843 (opens in a new tab)How to fix?
Upgrade langchain-core to version 0.3.85, 1.3.3 or higher.
Overview
langchain-core is a Building applications with LLMs through composability
Affected versions of this package are vulnerable to Deserialization of Untrusted Data in the load process. An attacker can instantiate trusted classes with untrusted constructor arguments by submitting specially crafted serialized payloads as structured input, which are then deserialized. This can lead to persistent data poisoning, prompt injection, behavior manipulation, credential disclosure, or unintended server-side requests if the deserialized objects perform sensitive actions during initialization.
Details
Serialization is a process of converting an object into a sequence of bytes which can be persisted to a disk or database or can be sent through streams. The reverse process of creating object from sequence of bytes is called deserialization. Serialization is commonly used for communication (sharing objects between multiple hosts) and persistence (store the object state in a file or a database). It is an integral part of popular protocols like Remote Method Invocation (RMI), Java Management Extension (JMX), Java Messaging System (JMS), Action Message Format (AMF), Java Server Faces (JSF) ViewState, etc.
Deserialization of untrusted data (CWE-502) is when the application deserializes untrusted data without sufficiently verifying that the resulting data will be valid, thus allowing the attacker to control the state or the flow of the execution.