Vulnerability-Lookup

PYSEC-2026-4028

Vulnerability from pysec - Published: 2026-10-01 16:38 - Updated: 2026-10-01 17:10

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

7.4 (High)


                  
                    CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N

9.1 (Critical)


                  
                    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

Impacted products

Name	purl
chainlit	pkg:pypi/chainlit

Aliases

JSON

To clipboard

{
  "affected": [
    {
      "package": {
        "ecosystem": "PyPI",
        "name": "chainlit",
        "purl": "pkg:pypi/chainlit"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "2.10.1"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "0.1.0",
        "0.1.1",
        "0.1.101",
        "0.1.102",
        "0.1.103",
        "0.2.0",
        "0.2.1",
        "0.2.101",
        "0.2.102",
        "0.2.103",
        "0.2.104",
        "0.2.105",
        "0.2.106",
        "0.2.107",
        "0.2.108",
        "0.2.109",
        "0.2.110",
        "0.2.111",
        "0.3.0",
        "0.4.0",
        "0.4.1",
        "0.4.101",
        "0.4.2",
        "0.4.3",
        "0.5.0",
        "0.5.1",
        "0.5.2",
        "0.6.0",
        "0.6.1",
        "0.6.2",
        "0.6.3",
        "0.6.4",
        "0.6.401",
        "0.6.402",
        "0.7.0",
        "0.7.1",
        "0.7.2",
        "0.7.3",
        "0.7.301",
        "0.7.400",
        "0.7.500",
        "0.7.501",
        "0.7.600rc0",
        "0.7.600rc1",
        "0.7.601rc0",
        "0.7.602",
        "0.7.602rc0",
        "0.7.603",
        "0.7.604",
        "0.7.604rc0",
        "0.7.604rc1",
        "0.7.604rc2",
        "0.7.700",
        "1.0.0",
        "1.0.0rc0",
        "1.0.0rc1",
        "1.0.0rc2",
        "1.0.0rc3",
        "1.0.100",
        "1.0.101",
        "1.0.200",
        "1.0.300",
        "1.0.301",
        "1.0.400",
        "1.0.401",
        "1.0.500",
        "1.0.501",
        "1.0.502",
        "1.0.503",
        "1.0.504",
        "1.0.505",
        "1.0.506",
        "1.1.0",
        "1.1.0rc0",
        "1.1.0rc1",
        "1.1.101",
        "1.1.200",
        "1.1.201",
        "1.1.202",
        "1.1.300",
        "1.1.300rc0",
        "1.1.300rc1",
        "1.1.300rc2",
        "1.1.300rc3",
        "1.1.300rc4",
        "1.1.300rc5",
        "1.1.301",
        "1.1.302",
        "1.1.303",
        "1.1.304",
        "1.1.305",
        "1.1.306",
        "1.1.400",
        "1.1.400rc0",
        "1.1.400rc1",
        "1.1.401",
        "1.1.402",
        "1.1.403rc0",
        "1.1.404",
        "1.2.0",
        "1.2.0rc0",
        "1.3.0",
        "1.3.0rc0",
        "1.3.0rc1",
        "1.3.1",
        "1.3.2",
        "2.0.0",
        "2.0.1",
        "2.0.2",
        "2.0.3",
        "2.0.4",
        "2.0.5",
        "2.0.6",
        "2.0.601",
        "2.0.602",
        "2.0.603",
        "2.0.dev0",
        "2.0.dev1",
        "2.0.dev2",
        "2.0rc0",
        "2.0rc1",
        "2.1.0",
        "2.1.1",
        "2.1.2",
        "2.10.0",
        "2.2.0",
        "2.2.1",
        "2.3.0",
        "2.4.0",
        "2.4.0rc0",
        "2.4.1",
        "2.4.2",
        "2.4.201",
        "2.4.3",
        "2.4.301",
        "2.4.302",
        "2.4.400",
        "2.5.5",
        "2.6.0",
        "2.6.1",
        "2.6.2",
        "2.6.3",
        "2.6.4",
        "2.6.5",
        "2.6.6",
        "2.6.7",
        "2.6.8",
        "2.6.9",
        "2.7.0",
        "2.7.1",
        "2.7.1.1",
        "2.7.2",
        "2.8.0",
        "2.8.1",
        "2.8.2",
        "2.8.3",
        "2.8.4",
        "2.8.5",
        "2.9.0",
        "2.9.1",
        "2.9.2",
        "2.9.3",
        "2.9.4",
        "2.9.5",
        "2.9.6"
      ]
    }
  ],
  "aliases": [
    "CVE-2026-56104",
    "GHSA-c39v-8hrw-h448"
  ],
  "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\u0027s permissions and roles, enabling unauthorized invocation of tools and access to data restricted to the authenticated victim.",
  "id": "PYSEC-2026-4028",
  "modified": "2026-10-01T17:10:18.842884Z",
  "published": "2026-10-01T16:38:28.448202Z",
  "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"
    },
    {
      "type": "PACKAGE",
      "url": "https://pypi.org/project/chainlit"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/advisories/GHSA-c39v-8hrw-h448"
    }
  ],
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N",
      "type": "CVSS_V3"
    },
    {
      "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",
      "type": "CVSS_V4"
    }
  ],
  "summary": "Chainlit contains a session hijacking vulnerability"
}

CVE-2026-56104 (GCVE-0-2026-56104)

Vulnerability from cvelistv5 – Published: 2026-06-22 14:17 – Updated: 2026-07-14 21:34 X_Open Source

Title

Chainlit < 2.10.1 Session Hijacking via WebSocket Session Restoration

Summary

Severity

8.8 (High)


                        
                          CVSS:4.0/AV:N/AC:H/AT:N/PR:L/UI:N/VC:H/VI:H/VA:N/SC:H/SI:H/SA:N

8.2 (High)


                        
                          CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:N

SSVC

Exploitation: none Automatable: no Technical Impact: total

CISA Coordinator · CISA-ADP (v2.0.3)

Decision recorded 2026-06-22 16:06 UTC

CWE

CWE-862 - Missing Authorization

Assigner

VulnCheck mitre root Scorecard

References

4 references

URL	Tags
https://github.com/Chainlit/chainlit/releases/tag…	release-notes
https://github.com/Chainlit/chainlit/pull/2857	issue-tracking
https://github.com/Chainlit/chainlit/commit/5effb…	patch
https://www.vulncheck.com/advisories/chainlit-ses…	third-party-advisory

Impacted products

1 product

Vendor	Product	Version
Chainlit	chainlit	Affected: 0 , < 2.10.1 (semver) cpe:2.3:a:chainlit:chainlit::::::::

Date Public

2026-05-24 00:00

Credits

Tanguy Snoeck

Show details on NVD website

JSON

To clipboard

{
  "containers": {
    "adp": [
      {
        "metrics": [
          {
            "other": {
              "content": {
                "id": "CVE-2026-56104",
                "options": [
                  {
                    "Exploitation": "none"
                  },
                  {
                    "Automatable": "no"
                  },
                  {
                    "Technical Impact": "total"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2026-06-22T16:06:42.802313Z",
                "version": "2.0.3"
              },
              "type": "ssvc"
            }
          }
        ],
        "providerMetadata": {
          "dateUpdated": "2026-06-22T16:06:48.051Z",
          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
        },
        "title": "CISA ADP Vulnrichment"
      }
    ],
    "cna": {
      "affected": [
        {
          "defaultStatus": "affected",
          "packageURL": "pkg:github/Chainlit/chainlit",
          "product": "chainlit",
          "repo": "https://github.com/Chainlit/chainlit",
          "vendor": "Chainlit",
          "versions": [
            {
              "lessThan": "2.10.1",
              "status": "affected",
              "version": "0",
              "versionType": "semver"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:a:chainlit:chainlit:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "2.10.1",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "credits": [
        {
          "lang": "en",
          "type": "finder",
          "value": "Tanguy Snoeck"
        }
      ],
      "datePublic": "2026-05-24T00:00:00.000Z",
      "descriptions": [
        {
          "lang": "en",
          "value": "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\u0027s permissions and roles, enabling unauthorized invocation of tools and access to data restricted to the authenticated victim."
        }
      ],
      "metrics": [
        {
          "cvssV4_0": {
            "Automatable": "NOT_DEFINED",
            "Recovery": "NOT_DEFINED",
            "Safety": "NOT_DEFINED",
            "attackComplexity": "HIGH",
            "attackRequirements": "NONE",
            "attackVector": "NETWORK",
            "baseScore": 8.8,
            "baseSeverity": "HIGH",
            "exploitMaturity": "NOT_DEFINED",
            "privilegesRequired": "LOW",
            "providerUrgency": "NOT_DEFINED",
            "subAvailabilityImpact": "NONE",
            "subConfidentialityImpact": "HIGH",
            "subIntegrityImpact": "HIGH",
            "userInteraction": "NONE",
            "valueDensity": "NOT_DEFINED",
            "vectorString": "CVSS:4.0/AV:N/AC:H/AT:N/PR:L/UI:N/VC:H/VI:H/VA:N/SC:H/SI:H/SA:N",
            "version": "4.0",
            "vulnAvailabilityImpact": "NONE",
            "vulnConfidentialityImpact": "HIGH",
            "vulnIntegrityImpact": "HIGH",
            "vulnerabilityResponseEffort": "NOT_DEFINED"
          },
          "format": "CVSS",
          "scenarios": [
            {
              "lang": "en",
              "value": "GENERAL"
            }
          ]
        },
        {
          "cvssV3_1": {
            "attackComplexity": "HIGH",
            "attackVector": "NETWORK",
            "availabilityImpact": "NONE",
            "baseScore": 8.2,
            "baseSeverity": "HIGH",
            "confidentialityImpact": "HIGH",
            "integrityImpact": "HIGH",
            "privilegesRequired": "LOW",
            "scope": "CHANGED",
            "userInteraction": "NONE",
            "vectorString": "CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:N",
            "version": "3.1"
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          "format": "CVSS",
          "scenarios": [
            {
              "lang": "en",
              "value": "GENERAL"
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          ]
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      ],
      "problemTypes": [
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          "descriptions": [
            {
              "cweId": "CWE-862",
              "description": "Missing Authorization",
              "lang": "en",
              "type": "CWE"
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      ],
      "providerMetadata": {
        "dateUpdated": "2026-07-14T21:34:00.565Z",
        "orgId": "83251b91-4cc7-4094-a5c7-464a1b83ea10",
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      "references": [
        {
          "name": "Release Notes",
          "tags": [
            "release-notes"
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          "url": "https://github.com/Chainlit/chainlit/releases/tag/2.10.1"
        },
        {
          "name": "Pull Request",
          "tags": [
            "issue-tracking"
          ],
          "url": "https://github.com/Chainlit/chainlit/pull/2857"
        },
        {
          "name": "Patch Commit",
          "tags": [
            "patch"
          ],
          "url": "https://github.com/Chainlit/chainlit/commit/5effb664f1e0af4a4f0a42fe63ea979676039a7f"
        },
        {
          "tags": [
            "third-party-advisory"
          ],
          "url": "https://www.vulncheck.com/advisories/chainlit-session-hijacking-via-websocket-session-restoration"
        }
      ],
      "source": {
        "discovery": "UNKNOWN"
      },
      "tags": [
        "x_open-source"
      ],
      "title": "Chainlit \u003c 2.10.1 Session Hijacking via WebSocket Session Restoration",
      "x_generator": {
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  "cveMetadata": {
    "assignerOrgId": "83251b91-4cc7-4094-a5c7-464a1b83ea10",
    "assignerShortName": "VulnCheck",
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    "datePublished": "2026-06-22T14:17:52.640Z",
    "dateReserved": "2026-06-18T19:15:10.650Z",
    "dateUpdated": "2026-07-14T21:34:00.565Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}

GHSA-C39V-8HRW-H448

Vulnerability from github – Published: 2026-06-22 18:34 – Updated: 2026-09-21 22:21

Summary

Chainlit contains a session hijacking vulnerability

Details

Severity

7.4 (High)


                  
                    CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N

9.1 (Critical)


                  
                    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

Show details on source website

JSON

To clipboard

{
  "affected": [
    {
      "package": {
        "ecosystem": "PyPI",
        "name": "chainlit"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "2.10.1"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-56104"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-862"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-09-21T22:21:35Z",
    "nvd_published_at": "2026-06-22T16:16:40Z",
    "severity": "CRITICAL"
  },
  "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\u0027s permissions and roles, enabling unauthorized invocation of tools and access to data restricted to the authenticated victim.",
  "id": "GHSA-c39v-8hrw-h448",
  "modified": "2026-09-21T22:21:35Z",
  "published": "2026-06-22T18:34:16Z",
  "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"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N",
      "type": "CVSS_V3"
    },
    {
      "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",
      "type": "CVSS_V4"
    }
  ],
  "summary": "Chainlit contains a session hijacking vulnerability"
}

Sightings

Author	Source	Type	Date	Other

Nomenclature

Seen: The vulnerability was mentioned, discussed, or observed by the user.
Confirmed: The vulnerability has been validated from an analyst's perspective.
Published Proof of Concept: A public proof of concept is available for this vulnerability.
Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
Not confirmed: The user expressed doubt about the validity of the vulnerability.
Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.

The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base model, served locally by ML-Gateway. They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
Browse all ATT&CK techniques and the vulnerabilities related to each.

Related by attack behaviour

Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.

Action not permitted

PYSEC-2026-4028

CVE-2026-56104 (GCVE-0-2026-56104)

GHSA-C39V-8HRW-H448

Tags

Sightings

Nomenclature

Related by attack behaviour