CVE-2025-49651: Backend.ai Backend.AI Missing Authorization Vulnerability Vulnerability

HIGH
Advisory Identifier: GHSA-h889-475r-wfmm
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CVSS 8.1
CWE-862
Published
Advisory Summary

CVE-2025-49651 is a HIGH (CVSS 8.1) backend.ai missing authorization vulnerability vulnerability (CWE-862: Missing Authorization) affecting Backend.ai libraries in the PyPI ecosystem. The issue involves backend.ai missing authorization vulnerability. Remediation is available in the latest vendor maintenance releases.

CVE-2025-49651 at a Glance

CVE Identifier CVE-2025-49651
GHSA Identifier GHSA-h889-475r-wfmm
Severity HIGH
CVSS v3.1 Base Score 8.1
CWE Classification CWE-862: Missing Authorization
Affected Product Backend.ai
Package Ecosystem PyPI
Published Date
Last Updated

Security Impact

CVSS: 8.1

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:H).

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 High (A:H)

How to Fix CVE-2025-49651

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

backend.ai fixed: Latest secure release 
pip install backend.ai>=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 backend.ai

How to Check if You Are Affected

To determine whether your Python environment is affected by CVE-2025-49651, inspect your installed packages using pip:

pip show backend.ai

Analyze the terminal output to locate any version of Backend.ai 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 backend.ai 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 Backend.ai, 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

Missing Authorization in Lablup's BackendAI allows attackers to takeover all active sessions; Accessing, stealing, or altering any data accessible in the session. This vulnerability exists in all current versions of BackendAI. NOTE: The maintainers of BackendAI do not consider this report to fit with their threat model and advise users to follow security advice from https://github.com/lablup/backend.ai/pull/7587 in their instances to protect themselves from the conditions that would lead to the situation described in the CVE record.

CVE-2025-49651 Affected Backend.ai Versions

1 component(s)
Product / Package Ecosystem Affected Versions Fixed Version
backend.ai
pypi/backend.ai
PyPI
≤ 25.3.3

References

NVD — CVE-2025-49651 NVD
https://nvd.nist.gov/vuln/detail/CVE-2025-49651
Backend.ai Source Repository REPOSITORY
https://github.com/lablup/backend.ai/pull/7587
Backend.ai Source Repository REPOSITORY
https://github.com/lablup/backend.ai
Backend.ai Security Information SECURITY
https://hiddenlayer.com/sai_security_advisor/2025-05-backendai-49653
Backend.ai Security Information SECURITY
https://hiddenlayer.com/sai_security_advisor/2025-06-backendai

Frequently Asked Questions

What is CVE-2025-49651?
CVE-2025-49651 is a security vulnerability in Backend.ai involving Backend.AI Missing Authorization vulnerability under CWE-862: Missing Authorization.
Which Backend.ai versions are affected?
Affected versions include releases prior to current release patches across affected packages: backend.ai.
What version fixes CVE-2025-49651?
Upgrading to current release patches (or the latest patched release for your respective branch) resolves the vulnerability.
Is backend.ai affected?
Yes, backend.ai 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-2025-49651?
CVE-2025-49651 has a CVSS v3.1 base score of 8.1 (HIGH) with vector string CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H.
What CWE is associated with CVE-2025-49651?
CVE-2025-49651 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-2025-49651?
Run the dependency tree command: 'pip show backend.ai'. 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-h889-475r-wfmm",
  "modified" : "2026-01-21T14:46:26Z",
  "published" : "2025-06-09T18:32:17Z",
  "aliases" : [ "CVE-2025-49651" ],
  "summary" : "Backend.AI Missing Authorization vulnerability",
  "details" : "Missing Authorization in Lablup's BackendAI allows attackers to takeover all active sessions; Accessing, stealing, or altering any data accessible in the session. This vulnerability exists in all current versions of BackendAI.\n\nNOTE: The maintainers of BackendAI do not consider this report to fit with their threat model and advise users to follow security advice from https://github.com/lablup/backend.ai/pull/7587 in their instances to protect themselves from the conditions that would lead to the situation described in the CVE record.",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "PyPI",
      "name" : "backend.ai"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "last_affected" : "25.3.3"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2025-49651"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/lablup/backend.ai/pull/7587"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/lablup/backend.ai"
  }, {
    "type" : "WEB",
    "url" : "https://hiddenlayer.com/sai_security_advisor/2025-05-backendai-49653"
  }, {
    "type" : "WEB",
    "url" : "https://hiddenlayer.com/sai_security_advisor/2025-06-backendai"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-862" ],
    "severity" : "HIGH",
    "github_reviewed" : true,
    "github_reviewed_at" : "2025-06-11T16:51:42Z",
    "nvd_published_at" : "2025-06-09T18:15:26Z"
  }
}