CVE-2026-91774

Yao through v1.0.0-rc22 Missing Authorization via OpenAPI team endpoint

Published Sep 15, 2026 CVSS 4.0 · 5.3 Medium EPSS < 1% KEV · Not listed

Description

Yao through v1.0.0-rc22 authenticates but fails to authorize the GET /user/teams/:id endpoint, allowing any logged-in user to read full team records. Attackers can supply a known team identifier to retrieve sensitive team data including name, description, owner information, and settings without membership verification.

Analysis

Technical impact

The vulnerability is due to a missing authorization check on the GET /user/teams/:id endpoint in Yao through v1.0.0-rc22. Any authenticated user can specify a team identifier and retrieve full details about that team—including name, description, owner information, and settings—without verifying membership. This results in unauthorized disclosure of internal team data (CWE-862).

Affected Systems

The flaw affects YaoApp's Yao application, specifically version 1.0.0-rc22 and any earlier releases that contain the unpatched code. Users should verify the version they are running to determine if the vulnerability applies.

Risk and Exploitability

The CVSS score of 5.3 reflects a moderate risk; exploitation requires only authentication, which can be achieved with a legitimate user account or a compromised one. The EPSS score of < 1% indicates a very low likelihood of active exploitation in the wild, and the vulnerability is not listed in CISA's KEV catalog. Nonetheless, the ability to read detailed team information from any authenticated session raises the potential for internal data leakage and warrants timely remediation.

Affected Products

Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).

Vendor Product Default status Versions

YaoApp

yao

unaffected

Version	Status	Constraints
`0`	affected	≤ 1.0.0-rc22

No data.

Vendor Product Versions

Yaoapp

Yao

Version	Status	Scheme	Platform
`[0,1.0.0-rc22]`	affected	generic	—

Remediation

No solution or workaround provided in the CVE record.

OpenCVE Recommended Actions

Apply any available vendor patch or upgrade to a version that includes an authorization check for the /user/teams/:id endpoint.
Until an official patch is released, configure the application to enforce that only members of the requested team can access /user/teams/:id by adding custom authorization logic or access controls.
Enable logging for all requests to /user/teams/:id and monitor for anomalous activity; consider implementing rate limiting to reduce the risk of enumeration attacks.

Generated by OpenCVE AI on September 17, 2026 at 19:06 UTC.

Tracking

Advisories

No advisories available

Metrics

Attack Vector Network

Attack Complexity Low

Privileges Required Low

Attack Requirements None

User Interaction None

Vulnerable System Confidentiality Impact Low

Vulnerable System Integrity Impact None

Vulnerable System Availability Impact None

Subsequent System Confidentiality Impact None

Subsequent System Integrity Impact None

Subsequent System Availability Impact None

Attack Vector Network

Attack Complexity Low

Privileges Required Low

Scope Unchanged

Confidentiality Impact Low

Integrity Impact None

Availability Impact None

User Interaction None

No CVSS v3.0

No CVSS v2

This CVE is not in the KEV list.

Exploit prediction score: < 1% (0.342% probability within 30 days)

Exploitation none

Automatable no

Technical Impact partial

References

Link	Providers
https://github.com/YaoApp/yao
https://github.com/YaoApp/yao/blob/v1.0.0-rc22/openapi/oauth/providers/user/team.go#L37-L55
https://github.com/YaoApp/yao/blob/v1.0.0-rc22/openapi/user/team.go#L80-L149
https://github.com/YaoApp/yao/issues/1553
https://www.vulncheck.com/advisories/yao-through-1.0.0-rc22-missing-authorization-via-openapi-team-endpoint

History

Sep 17, 2026 8:30 PM First appearance in the feed. Affected vendors updated. Scoring metrics updated View changes

Type	Values Removed	Values Added
First Time appeared		Yaoapp Yaoapp yao
Vendors & Products		Yaoapp Yaoapp yao
Metrics		ssvc `{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}`

Sep 15, 2026 1:45 AM Description updated. Title updated. Weaknesses updated. Added references. Scoring metrics updated View changes

Type	Values Removed	Values Added
Description		Yao through v1.0.0-rc22 authenticates but fails to authorize the GET /user/teams/:id endpoint, allowing any logged-in user to read full team records. Attackers can supply a known team identifier to retrieve sensitive team data including name, description, owner information, and settings without membership verification.
Title		Yao through v1.0.0-rc22 Missing Authorization via OpenAPI team endpoint
Weaknesses		CWE-862
References		https://github.com/YaoApp/yao https://github.com/YaoApp/yao/blob/v1.0.0-rc22/openapi/oauth/providers/user/team.go#L37-L55 https://github.com/YaoApp/yao/blob/v1.0.0-rc22/openapi/user/team.go#L80-L149 https://github.com/YaoApp/yao/issues/1553 https://www.vulncheck.com/advisories/yao-through-1.0.0-rc22-missing-authorization-via-openapi-team-endpoint
Metrics		cvssV3_1 `{'score': 4.3, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N'}` cvssV4_0 `{'score': 5.3, 'vector': 'CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N'}`