Vulnerabilities in pkg:pypi/chainlit

PACKAGE
Advisory Identifier: GHSA-c39v-8hrw-h448
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Advisory Summary

CVE-2026-56104 is a CRITICAL (CVSS 7.4) chainlit contains a session hijacking vulnerability (CWE-862: Missing Authorization) affecting Chainlit libraries in the PyPI ecosystem. The issue involves chainlit contains a session hijacking vulnerability. Remediation is available by upgrading affected packages to version 2.10.1.

5 Known Advisory Record(s)
Package Vulnerability Intelligence

pkg:pypi/chainlit

5 Known Advisory Record(s)

Vulnerability advisories affecting package pkg:pypi/chainlit. Select an advisory below to view technical details or fixes.

Advisory ID CVE / NVD Severity Summary
GHSA-c39v-8hrw-h448 CVE-2026-56104 CRITICAL Chainlit contains a session hijacking vulnerability
GHSA-hvfh-5mj3-5f3j CVE-2026-45019 HIGH Chainlist has SSRF via MCP SSE and streamable-http transports that allows unauthenticated internal network access
GHSA-w3fx-mc44-mf6j CVE-2026-45018 CRITICAL Chainlit has command injection via MCP stdio transport that allows unauthenticated remote code execution
GHSA-2g59-m95p-pgfq CVE-2026-22219 HIGH Chainlit contain a server-side request forgery (SSRF) vulnerability
GHSA-v492-6xx2-p57g CVE-2025-68492 LOW Chainlit contains an authorization bypass vulnerability

CVE-2026-56104 at a Glance

CVE Identifier CVE-2026-56104
GHSA Identifier GHSA-c39v-8hrw-h448
Severity CRITICAL
CVSS v3.1 Base Score 7.4
CWE Classification CWE-862: Missing Authorization
Affected Product Chainlit
Package Ecosystem PyPI
Published Date
Last Updated

Security Impact

CVSS: 7.4

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

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

How to Fix CVE-2026-56104

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

chainlit fixed: 2.10.1 
pip install chainlit>=2.10.1
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 chainlit

How to Check if You Are Affected

To determine whether your Python environment is affected by CVE-2026-56104, inspect your installed packages using pip:

pip show chainlit

Analyze the terminal output to locate any version of Chainlit in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 2.10.1), your application is affected.

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

Technical Details

Vulnerability Mechanism & Technical Analysis

This vulnerability is classified under CWE-862: Missing Authorization, where the product does not perform an authorization check when an actor attempts to access a resource or perform an action. In Chainlit, 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

Chainlit before 2.10.1 contains a session hijacking vulnerability that allows unauthenticated attackers to restore and inherit authenticated user sessions by presenting a valid sessionId during WebSocket session restoration without ownership verification. Attackers can exploit the restore_existing_session path to assume a victim's permissions and roles, enabling unauthorized invocation of tools and access to data restricted to the authenticated victim.

CVE-2026-56104 Affected Chainlit Versions

1 component(s)
Fixed Versions:
2.10.1
Product / Package Ecosystem Affected Versions Fixed Version
chainlit
pypi/chainlit
PyPI
< 2.10.1
2.10.1

References

NVD — CVE-2026-56104 NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-56104
Chainlit Source Repository REPOSITORY
https://github.com/Chainlit/chainlit/pull/2857
Security Fix Commit FIX COMMIT
https://github.com/Chainlit/chainlit/commit/5effb664f1e0af4a4f0a42fe63ea979676039a7f
Chainlit Source Repository REPOSITORY
https://github.com/Chainlit/chainlit
Chainlit Release RELEASE
https://github.com/Chainlit/chainlit/releases/tag/2.10.1
www.vulncheck.com/advisories/chainlit... WEB
https://www.vulncheck.com/advisories/chainlit-session-hijacking-via-websocket-session-restoration

Frequently Asked Questions

What is CVE-2026-56104?
CVE-2026-56104 is a security vulnerability in Chainlit involving Chainlit contains a session hijacking vulnerability under CWE-862: Missing Authorization.
Which Chainlit versions are affected?
Affected versions include releases prior to 2.10.1 across affected packages: chainlit.
What version fixes CVE-2026-56104?
Upgrading to 2.10.1 (or the latest patched release for your respective branch) resolves the vulnerability.
Is chainlit affected?
Yes, chainlit is affected in releases prior to 2.10.1. Upgrade your dependency to 2.10.1 or later.
What is the CVSS score of CVE-2026-56104?
CVE-2026-56104 has a CVSS v3.1 base score of 7.4 (CRITICAL) with vector string CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N.
What CWE is associated with CVE-2026-56104?
CVE-2026-56104 is classified under CWE-862: Missing Authorization (The product does not perform an authorization check when an actor attempts to access a resource or perform an action.).
How can I check PyPI dependencies for CVE-2026-56104?
Run the dependency tree command: 'pip show chainlit'. 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-c39v-8hrw-h448",
  "modified" : "2026-09-21T22:21:35Z",
  "published" : "2026-06-22T18:34:16Z",
  "aliases" : [ "CVE-2026-56104" ],
  "summary" : "Chainlit contains a session hijacking vulnerability",
  "details" : "Chainlit before 2.10.1 contains a session hijacking vulnerability that allows unauthenticated attackers to restore and inherit authenticated user sessions by presenting a valid sessionId during WebSocket session restoration without ownership verification. Attackers can exploit the restore_existing_session path to assume a victim's permissions and roles, enabling unauthorized invocation of tools and access to data restricted to the authenticated victim.",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N"
  }, {
    "type" : "CVSS_V4",
    "score" : "CVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "PyPI",
      "name" : "chainlit"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "2.10.1"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2026-56104"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/Chainlit/chainlit/pull/2857"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/Chainlit/chainlit/commit/5effb664f1e0af4a4f0a42fe63ea979676039a7f"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/Chainlit/chainlit"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/Chainlit/chainlit/releases/tag/2.10.1"
  }, {
    "type" : "WEB",
    "url" : "https://www.vulncheck.com/advisories/chainlit-session-hijacking-via-websocket-session-restoration"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-862" ],
    "severity" : "CRITICAL",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-09-21T22:21:35Z",
    "nvd_published_at" : "2026-06-22T16:16:40Z"
  }
}