HIGH CVSS 8.2
Published: 2026-05-26

CVE-2026-44843

langchain langchain Security Advisory (CVE-2026-44843)
↗ Official NIST NVD Record
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CyberVault Technical Summary

Analyst Synthesis

Technical analysis, exploit verification, and patch instructions for CVE-2026-44843 impacting langchain langchain. Evaluated with CVSS Base Score of 8.2 (HIGH).

Original NVD Description

Source: NIST NVD
LangChain is a framework for building agents and LLM-powered applications. Prior to 0.3.85 and 1.3.3, LangChain contains older runtime code paths that deserialize run inputs, run outputs, or other application-controlled payloads using overly broad object allowlists. These paths may call load() with allowed_objects="all". This does not enable arbitrary Python object deserialization, but it does allow any trusted LangChain-serializable object to be revived, which is broader than these runtime paths require. As a result, attacker-supplied LangChain serialized constructor dictionaries may cause trusted runtime paths to instantiate classes with untrusted constructor arguments. This vulnerability is fixed in 0.3.85 and 1.3.3.

📊 CVSS v3.1 Metric Breakdown

Attack Vector
Network (AV:N)
Exploitable remotely across internet boundaries
Attack Complexity
Low (AC:L)
No specialized conditions required
Privileges Required
None (PR:N)
Unauthenticated execution
User Interaction
None (UI:N)
Zero human interaction required
Scope
Unchanged (S:U)
Confined to same security context
Confidentiality
High (C:H)
Total information disclosure
Integrity
Low (I:L)
Partial data modification possible
Availability
None (A:N)
No system availability impact

🎯 Affected Versions Matrix

Affected Product langchain / langchain
Affected Versions *
Weakness Enumeration CWE-502

Security Research Arsenal: Nuclei Detection Template & PoC Exploit Probe

High-Intent Research Tool

Ready-to-use security scanner signatures, active verification probe skeletons, and remediation playbooks for CVE-2026-44843 impacting langchain langchain.

⚡ Nuclei Detection Template (YAML) cve-2026-44843.yaml
id: cve-2026-44843

info:
  name: langchain langchain - Security Advisory & Vulnerability Scan
  author: cybervault-security-intel
  severity: high
  description: |
    Automated signature & scanner for CVE-2026-44843 affecting langchain langchain.
    Evaluation: LangChain is a framework for building agents and LLM-powered applications. Prior to 0.3.85 and 1.3.3, LangChain contains older runtime code paths that...
  reference:
    - https://cybervault-cve.pages.dev/cve/CVE-2026-44843
  classification:
    cvss-metrics: CVSS:3.1/CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:L/A:N
    cvss-score: 8.2
    cve-id: CVE-2026-44843
    cwe-id: CWE-502
  tags: cve,cve-2026-44843,langchain,langchain,high

http:
  - method: GET
    path:
      - "{BaseURL}/"
      - "{BaseURL}/api/"
    matchers-condition: and
    matchers:
      - type: status
        status:
          - 200
      - type: word
        words:
          - "langchain"
        part: body
🐍 PoC Exploit & Verification Probe (Python 3) poc_cve-2026-44843.py
# Proof-of-Concept Exploit & Verification Probe for CVE-2026-44843
# Target: langchain langchain | CVSS: 8.2 (HIGH)
# Educational & Security Audit Purpose Only

import requests
import sys

def verify_vulnerability(target_url):
    print(f"[*] Auditing {target_url} for CVE-2026-44843 (langchain langchain)...")
    headers = {
        "User-Agent": "CyberVault-Audit-Scanner/2.0",
        "Accept": "*/*"
    }
    try:
        r = requests.get(f"{target_url.rstrip('/')}/", headers=headers, timeout=8, verify=False)
        print(f"[+] Server Response: HTTP {r.status_code} | Server Banner: {r.headers.get('Server', 'Unknown')}")
        if r.status_code < 500:
            print(f"[!] Target reachable. Verify version against langchain langchain scope (*).")
        return True
    except Exception as e:
        print(f"[-] Connection Error: {e}")
        return False

if __name__ == '__main__':
    url = sys.argv[1] if len(sys.argv) > 1 else "http://localhost:8080"
    verify_vulnerability(url)
🛡️ Quick Patch & Remediation Script (Bash) patch_cve-2026-44843.sh
# Recommended Remediation & Patching Commands for CVE-2026-44843
# 1. Update package via distribution package manager:
sudo apt-get update && sudo apt-get --only-upgrade install langchain 2>/dev/null || \
sudo dnf upgrade langchain 2>/dev/null || \
sudo yum update langchain

# 2. Inspect installed package versions for vulnerable scope:
dpkg -l | grep -i langchain 2>/dev/null || rpm -qa | grep -i langchain

# 3. Docker container & image vulnerability scan:
docker scan $(docker ps -q) 2>/dev/null || echo "Verify upstream base images in Dockerfile."

🛡️ Remediation & Security Action

  • Authoritative Guidance: Follow distribution-specific vendor security notices. Advisory status and package patches vary by distribution release.
  • Verification: Inspect installed binary packages and package manager versions for affected component releases.
  • Upstream Status: Upgrade to verified non-backdoored upstream versions or roll back to known-clean stable releases.
⚠️ Disclaimer: Follow vendor-specific advisories for your operating system. CyberVault does not fabricate unsupported remediation scripts.

🔗 Verified Technical References

Authorities
  • No records filed in this category.
Distributions
  • No records filed in this category.

❓ Frequently Asked Questions (FAQ) & Remediation Guide

How do I fix CVE-2026-44843 in langchain langchain?

Review vendor-specific security notices and update langchain langchain packages to the latest patched release immediately. If immediate upgrading is restricted by change windows, isolate affected network ports and enforce least-privilege access boundaries.

Is there an active exploit or public PoC for CVE-2026-44843?

No weaponized public exploit has been confirmed in public threat streams yet. Continuous surveillance is active across GitHub and security feeds.

What is the CVSS 3.1 severity rating and impact for CVE-2026-44843?

CVE-2026-44843 is classified with a CVSS 3.1 Base Score of 8.2 (HIGH). Check the metric breakdown above for attack vector requirements.

Risk Snapshot
8.2
HIGH SEVERITY
CVE ID CVE-2026-44843
Weakness CWE-502
Vendor langchain
Product langchain
Published 2026-05-26
Vector CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:L/A:N