Vulnerability-Lookup

CVE-2026-30857 (GCVE-0-2026-30857)

Vulnerability from cvelistv5 – Published: 2026-03-07 16:33 – Updated: 2026-03-09 18:24

Title

WeKnora: Unauthorized Cross‑Tenant Knowledge Base Cloning

Summary

WeKnora is an LLM-powered framework designed for deep document understanding and semantic retrieval. Prior to version 0.3.0, a cross-tenant authorization bypass in the knowledge base copy endpoint allows any authenticated user to clone (duplicate) another tenant’s knowledge base into their own tenant by knowing/guessing the source knowledge base ID. This enables bulk data exfiltration (document/FAQ content) across tenants. This issue has been patched in version 0.3.0.

Severity

5.3 (Medium)


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

SSVC

Exploitation: poc Automatable: no Technical Impact: partial

CISA Coordinator · CISA-ADP (v2.0.3)

Decision recorded 2026-03-09 17:52 UTC

CWE

CWE-639 - Authorization Bypass Through User-Controlled Key

Assigner

GitHub_M mitre root

References

1 reference

URL	Tags
https://github.com/Tencent/WeKnora/security/advis…	x_refsource_CONFIRM

Impacted products

1 product

Vendor	Product	Version	CPE status
Tencent	WeKnora	Affected: < 0.3.0	guessed

Show details on NVD website

JSON

To clipboard

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FKIE_CVE-2026-30857

Vulnerability from fkie_nvd - Published: 2026-03-07 17:15 - Updated: 2026-06-17 10:33

Severity

5.3 (Medium) - CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:N/A:N

Summary

References

	URL	Tags
	security-advisories@github.com	https://github.com/Tencent/WeKnora/security/advisories/GHSA-8rf9-c59g-f82f	Exploit, Vendor Advisory

Impacted products

	Vendor	Product	Version
	tencent	weknora	*

JSON

To clipboard

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  "affected": [
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      "affectedData": [
        {
          "product": "WeKnora",
          "vendor": "Tencent",
          "versions": [
            {
              "status": "affected",
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    }
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    },
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    }
  ],
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  "lastModified": "2026-06-17T10:33:02.683",
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GHSA-8RF9-C59G-F82F

Vulnerability from github – Published: 2026-03-06 23:55 – Updated: 2026-03-09 13:21

Summary

WeKnora has Unauthorized Cross‑Tenant Knowledge Base Cloning

Details

Summary

A cross-tenant authorization bypass in the knowledge base copy endpoint allows any authenticated user to clone (duplicate) another tenant’s knowledge base into their own tenant by knowing/guessing the source knowledge base ID. This enables bulk data exfiltration (document/FAQ content) across tenants, making the impact critical.

Details

The POST /api/v1/knowledge-bases/copy endpoint enqueues an asynchronous KB clone task using the caller-supplied source_id without verifying ownership (see internal/handler/knowledgebase.go).

// Create KB clone payload
payload := types.KBClonePayload{
  TenantID: tenantID.(uint64),
  TaskID:   taskID,
  SourceID: req.SourceID, // from attacker's input
  TargetID: req.TargetID,
}

payloadBytes, err := json.Marshal(payload)
if err != nil {
  logger.Errorf(ctx, "Failed to marshal KB clone payload: %v", err)
  c.Error(errors.NewInternalServerError("Failed to create task"))
  return
}

// Enqueue KB clone task to Asynq
task := asynq.NewTask(types.TypeKBClone, payloadBytes,
asynq.TaskID(taskID), asynq.Queue("default"), asynq.MaxRetry(3)) // enqueue task
info, err := h.asynqClient.Enqueue(task)
if err != nil {
  logger.Errorf(ctx, "Failed to enqueue KB clone task: %v", err)
  c.Error(errors.NewInternalServerError("Failed to enqueue task"))
  return
}

Then, the asynq task handler (ProcessKBClone) invokes the CopyKnowledgeBase service method to perform the clone operation (see internal/application/service/knowledge.go):

// Get source and target knowledge bases
srcKB, dstKB, err := s.kbService.CopyKnowledgeBase(ctx, payload.SourceID, payload.TargetID)
if err != nil {
    logger.Errorf(ctx, "Failed to copy knowledge base: %v", err)
    handleError(progress, err, "Failed to copy knowledge base configuration")
    return err
}

After that, the CopyKnowledgeBase method calls the repository method to load the source knowledge base (see internal/application/service/knowledgebase.go):

func (s *knowledgeBaseService) CopyKnowledgeBase(ctx context.Context,
    srcKB string, dstKB string,
) (*types.KnowledgeBase, *types.KnowledgeBase, error) {
    sourceKB, err := s.repo.GetKnowledgeBaseByID(ctx, srcKB)
    if err != nil {
        logger.Errorf(ctx, "Get source knowledge base failed: %v", err)
        return nil, nil, err
    }
    sourceKB.EnsureDefaults()
    tenantID := ctx.Value(types.TenantIDContextKey).(uint64)
    var targetKB *types.KnowledgeBase
    if dstKB != "" {
        targetKB, err = s.repo.GetKnowledgeBaseByID(ctx, dstKB)
        // ...
    }
    // ...
}

Note: until now, the tenant ID is correctly set in context to the attacker’s tenant (from the payload), which can be used to prevent cross-tenant access.

However, the repository method GetKnowledgeBaseByID loads knowledge bases by id only, allowing cross-tenant reads (see internal/application/repository/knowledgebase.go).

func (r *knowledgeBaseRepository) GetKnowledgeBaseByID(ctx context.Context, id string) (*types.KnowledgeBase, error) {
    var kb types.KnowledgeBase
    if err := r.db.WithContext(ctx).Where("id = ?", id).First(&kb).Error; err != nil {
        if errors.Is(err, gorm.ErrRecordNotFound) {
            return nil, ErrKnowledgeBaseNotFound
        }
        return nil, err
    }
    return &kb, nil
}

The data access layer fails to enforce tenant isolation because GetKnowledgeBaseByID only filters by ID and ignores the tenant_id present in the context. A secure implementation should enforce a tenant-scoped lookup (e.g., WHERE id = ? AND tenant_id = ?) or use a tenant-aware repository API to prevent cross-tenant access.

Service shallow-copies the KB configuration by calling GetKnowledgeBaseByID(ctx, srcKB) for the source KB, then creates a new KB under the attacker’s tenant while copying fields from the victim KB (internal/application/service/knowledgebase.go):

sourceKB, err := s.repo.GetKnowledgeBaseByID(ctx, srcKB) // not tenant-scoped
...
targetKB = &types.KnowledgeBase{
    ID:                    uuid.New().String(),
    Name:                  sourceKB.Name,
    Type:                  sourceKB.Type,
    Description:           sourceKB.Description,
    TenantID:              tenantID,
    ChunkingConfig:        sourceKB.ChunkingConfig,
    ImageProcessingConfig: sourceKB.ImageProcessingConfig,
    EmbeddingModelID:      sourceKB.EmbeddingModelID,
    SummaryModelID:        sourceKB.SummaryModelID,
    VLMConfig:             sourceKB.VLMConfig,
    StorageConfig:         sourceKB.StorageConfig,
    FAQConfig:             faqConfig,
}
targetKB.EnsureDefaults()
  if err := s.repo.CreateKnowledgeBase(ctx, targetKB); err != nil {
      return nil, nil, err
  }
}

PoC

Precondition: Attacker is authenticated in Tenant A and can obtain (or guess) a victim's knowledge base UUID belonging to Tenant B.

1) Authenticate as Tenant A and obtain a bearer token or API key.

2) Start a cross-tenant clone using the victim’s knowledge base ID as source_id:

curl -X POST http://localhost:8088/api/v1/knowledge-bases/copy \
  -H "Authorization: Bearer <ATTACKER_TOKEN>" \
  -H "Content-Type: application/json" \
  -d '{"source_id":"<VICTIM_KB_UUID>","target_id":""}'

3) Observe that the task is accepted: - HTTP 200 OK - Response contains a task_id and a message like "Knowledge base copy task started".

4) After the async task completes, a new knowledge base appears under Tenant A containing copied content/config from Tenant B.

Note: the copy can succeed even when models referenced by the source KB do not exist in the attacker tenant, indicating the workflow does not validate model ownership during copy.

PoC Video:

https://github.com/user-attachments/assets/8313fa44-5d5d-43f4-8ebd-f465c5a9d56e

Impact

This is a Broken Access Control (BOLA/IDOR) vulnerability enabling cross-tenant data exfiltration:

Any authenticated user can trigger a clone of a victim tenant’s knowledge base into their own tenant.
Results in bulk disclosure/duplication of knowledge base contents (documents/FAQ entries/chunks), plus associated configuration.

Severity

5.9 (Medium)


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

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{
  "affected": [
    {
      "database_specific": {
        "last_known_affected_version_range": "\u003c= 0.2.14"
      },
      "package": {
        "ecosystem": "Go",
        "name": "github.com/Tencent/WeKnora"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "0.3.0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-30857"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-639"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-03-06T23:55:47Z",
    "nvd_published_at": "2026-03-07T17:15:53Z",
    "severity": "MODERATE"
  },
  "details": "### Summary\nA cross-tenant authorization bypass in the knowledge base copy endpoint allows any authenticated user to clone (duplicate) another tenant\u2019s knowledge base into their own tenant by knowing/guessing the source knowledge base ID. This enables bulk data exfiltration (document/FAQ content) across tenants, making the impact critical.\n\n### Details\n\nThe `POST /api/v1/knowledge-bases/copy` endpoint enqueues an asynchronous KB clone task using the caller-supplied `source_id` without verifying ownership (see `internal/handler/knowledgebase.go`).\n```go\n// Create KB clone payload\npayload := types.KBClonePayload{\n  TenantID: tenantID.(uint64),\n  TaskID:   taskID,\n  SourceID: req.SourceID, // from attacker\u0027s input\n  TargetID: req.TargetID,\n}\n\npayloadBytes, err := json.Marshal(payload)\nif err != nil {\n  logger.Errorf(ctx, \"Failed to marshal KB clone payload: %v\", err)\n  c.Error(errors.NewInternalServerError(\"Failed to create task\"))\n  return\n}\n\n// Enqueue KB clone task to Asynq\ntask := asynq.NewTask(types.TypeKBClone, payloadBytes,\nasynq.TaskID(taskID), asynq.Queue(\"default\"), asynq.MaxRetry(3)) // enqueue task\ninfo, err := h.asynqClient.Enqueue(task)\nif err != nil {\n  logger.Errorf(ctx, \"Failed to enqueue KB clone task: %v\", err)\n  c.Error(errors.NewInternalServerError(\"Failed to enqueue task\"))\n  return\n}\n```\n\nThen, the asynq task handler (`ProcessKBClone`) invokes the `CopyKnowledgeBase` service method to perform the clone operation (see `internal/application/service/knowledge.go`):\n\n```go\n// Get source and target knowledge bases\nsrcKB, dstKB, err := s.kbService.CopyKnowledgeBase(ctx, payload.SourceID, payload.TargetID)\nif err != nil {\n    logger.Errorf(ctx, \"Failed to copy knowledge base: %v\", err)\n    handleError(progress, err, \"Failed to copy knowledge base configuration\")\n    return err\n}\n```\n\nAfter that, the `CopyKnowledgeBase` method calls the repository method to load the source knowledge base (see `internal/application/service/knowledgebase.go`):\n\n```go\nfunc (s *knowledgeBaseService) CopyKnowledgeBase(ctx context.Context,\n\tsrcKB string, dstKB string,\n) (*types.KnowledgeBase, *types.KnowledgeBase, error) {\n\tsourceKB, err := s.repo.GetKnowledgeBaseByID(ctx, srcKB)\n\tif err != nil {\n\t\tlogger.Errorf(ctx, \"Get source knowledge base failed: %v\", err)\n\t\treturn nil, nil, err\n\t}\n\tsourceKB.EnsureDefaults()\n\ttenantID := ctx.Value(types.TenantIDContextKey).(uint64)\n\tvar targetKB *types.KnowledgeBase\n\tif dstKB != \"\" {\n\t\ttargetKB, err = s.repo.GetKnowledgeBaseByID(ctx, dstKB)\n        // ...\n    }\n    // ...\n}\n```\n\n\n\u003e Note: until now, the tenant ID is correctly set in context to the attacker\u2019s tenant (from the payload), which can be used to prevent cross-tenant access.\n\nHowever, the repository method `GetKnowledgeBaseByID` loads knowledge bases by `id` only, allowing cross-tenant reads (see `internal/application/repository/knowledgebase.go`).\n\n```go\nfunc (r *knowledgeBaseRepository) GetKnowledgeBaseByID(ctx context.Context, id string) (*types.KnowledgeBase, error) {\n\tvar kb types.KnowledgeBase\n\tif err := r.db.WithContext(ctx).Where(\"id = ?\", id).First(\u0026kb).Error; err != nil {\n\t\tif errors.Is(err, gorm.ErrRecordNotFound) {\n\t\t\treturn nil, ErrKnowledgeBaseNotFound\n\t\t}\n\t\treturn nil, err\n\t}\n\treturn \u0026kb, nil\n}\n```\n\nThe data access layer fails to enforce tenant isolation because `GetKnowledgeBaseByID` only filters by ID and ignores the `tenant_id` present in the context. A secure implementation should enforce a tenant-scoped lookup (e.g., `WHERE id = ? AND tenant_id = ?`) or use a tenant-aware repository API to prevent cross-tenant access.\n\nService shallow-copies the KB configuration by calling `GetKnowledgeBaseByID(ctx, srcKB)` for the source KB, then creates a new KB under the attacker\u2019s tenant while copying fields from the victim KB (`internal/application/service/knowledgebase.go`):\n\n```go\nsourceKB, err := s.repo.GetKnowledgeBaseByID(ctx, srcKB) // not tenant-scoped\n...\ntargetKB = \u0026types.KnowledgeBase{\n    ID:                    uuid.New().String(),\n    Name:                  sourceKB.Name,\n    Type:                  sourceKB.Type,\n    Description:           sourceKB.Description,\n    TenantID:              tenantID,\n    ChunkingConfig:        sourceKB.ChunkingConfig,\n    ImageProcessingConfig: sourceKB.ImageProcessingConfig,\n    EmbeddingModelID:      sourceKB.EmbeddingModelID,\n    SummaryModelID:        sourceKB.SummaryModelID,\n    VLMConfig:             sourceKB.VLMConfig,\n    StorageConfig:         sourceKB.StorageConfig,\n    FAQConfig:             faqConfig,\n}\ntargetKB.EnsureDefaults()\n  if err := s.repo.CreateKnowledgeBase(ctx, targetKB); err != nil {\n      return nil, nil, err\n  }\n}\n```\n\n### PoC\n\nPrecondition: Attacker is authenticated in Tenant A and can obtain (or guess) a victim\u0027s knowledge base UUID belonging to Tenant B.\n\n1) Authenticate as Tenant A and obtain a bearer token or API key.\n\n2) Start a cross-tenant clone using the victim\u2019s knowledge base ID as `source_id`:\n\n```bash\ncurl -X POST http://localhost:8088/api/v1/knowledge-bases/copy \\\n  -H \"Authorization: Bearer \u003cATTACKER_TOKEN\u003e\" \\\n  -H \"Content-Type: application/json\" \\\n  -d \u0027{\"source_id\":\"\u003cVICTIM_KB_UUID\u003e\",\"target_id\":\"\"}\u0027\n```\n\n3) Observe that the task is accepted:\n- HTTP `200 OK`\n- Response contains a `task_id` and a message like `\"Knowledge base copy task started\"`.\n\n4) After the async task completes, a new knowledge base appears under Tenant A containing copied content/config from Tenant B.\n\n\u003e Note: the copy can succeed even when models referenced by the source KB do not exist in the attacker tenant, indicating the workflow does not validate model ownership during copy.\n\nPoC Video:\n\nhttps://github.com/user-attachments/assets/8313fa44-5d5d-43f4-8ebd-f465c5a9d56e\n\n### Impact\n\nThis is a Broken Access Control (BOLA/IDOR) vulnerability enabling cross-tenant data exfiltration:\n\n- Any authenticated user can trigger a clone of a victim tenant\u2019s knowledge base into their own tenant.\n- Results in bulk disclosure/duplication of knowledge base contents (documents/FAQ entries/chunks), plus associated configuration.",
  "id": "GHSA-8rf9-c59g-f82f",
  "modified": "2026-03-09T13:21:46Z",
  "published": "2026-03-06T23:55:47Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/Tencent/WeKnora/security/advisories/GHSA-8rf9-c59g-f82f"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-30857"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/Tencent/WeKnora"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N",
      "type": "CVSS_V3"
    }
  ],
  "summary": "WeKnora has Unauthorized Cross\u2011Tenant Knowledge Base Cloning"
}

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.

Detection rules are retrieved from Rulezet.

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.

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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

CVE-2026-30857 (GCVE-0-2026-30857)

FKIE_CVE-2026-30857

GHSA-8RF9-C59G-F82F

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