How should we interpret CVSS severity scores?

CVSS estimates technical severity, but it does not automatically equal business risk. Prioritize using context like internet exposure, asset criticality, known exploitation, and whether compensating controls exist. A Medium CVSS on an exposed production system can be more urgent than a Critical on an isolated non-production host.

Vulnerability Database

Q: What is a Vulnerability (CVE) and why does it matter?

A security vulnerability is a weakness in software, hardware, or configuration that can be exploited to compromise confidentiality, integrity, or availability. Many vulnerabilities are tracked as CVEs (Common Vulnerabilities and Exposures), which provide a standardized identifier so teams can coordinate patching, mitigation, and risk assessment across tools and vendors.

Q: What's the difference between a vulnerability, an exploit, and a zero-day?

A vulnerability is the underlying weakness. An exploit is the method or code used to take advantage of it. A zero-day is a vulnerability that is unknown to the vendor or has no publicly available fix when attackers begin using it. Risk increases sharply when exploitation becomes reliable or widespread.

Q: Why do vulnerabilities keep reappearing in our environment?

Recurring findings usually come from incomplete asset discovery, inconsistent patch management, inherited images, and configuration drift. In modern environments, you also need to watch the software supply chain: dependencies, containers, build pipelines, and third-party services can reintroduce the same weakness even after you patch a single host.

Q: How do we prioritize remediation without burning out the team?

Use a repeatable triage model: focus first on externally exposed assets, high-value systems (identity, VPN, email, production), vulnerabilities with known exploits, and issues that enable remote code execution or privilege escalation. Then enforce patch SLAs and track progress so remediation is steady, not reactive.

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352,262

Total vulnerabilities in the database

CVE-2026-28699 — code.gitea.io/gitea

Improper Access Control

Summary

Gitea fails to enforce OAuth2 access token scopes when the token is submitted via HTTP Basic authentication instead of a Bearer token. An OAuth2 application granted only read:user can use the same token as Authorization: Basic base64(<token>:x-oauth-basic) and perform write actions, including modifying profiles, adding email addresses, creating repositories, and deleting repositories as the authorizing user.

Details

Root cause: services/auth/basic.go accepts OAuth2 access tokens through the Basic auth path but does not store the token scope in the request context:

// services/auth/basic.go
if uid != 0 {
    store.GetData()[&quot;LoginMethod&quot;] = OAuth2TokenMethodName
    store.GetData()[&quot;IsApiToken&quot;] = true   // scope is NOT set
    return u, nil
}

The scope enforcement middleware in routers/api/v1/api.go exits early when ApiTokenScope is absent:

// routers/api/v1/api.go — tokenRequiresScopes
scope, scopeExists := ctx.Data[&quot;ApiTokenScope&quot;].(auth_model.AccessTokenScope)
if ctx.Data[&quot;IsApiToken&quot;] != true || !scopeExists {
    return   //&lt;- exits without checking scope, all actions permitted
}

When a token arrives via Bearer, ApiTokenScope is populated and scope checks apply normally. When the same token arrives via Basic auth, ApiTokenScope is never set, so tokenRequiresScopes returns immediately and no scope is enforced.

Suggested fix: When an OAuth2 access token is accepted in services/auth/basic.go, populate ApiTokenScope in the request context identically to the Bearer-token OAuth2 path.

PoC

Create an OAuth2 application in Gitea.
Authorize it as a normal user with scope read:user only.
Take the resulting access token and call a write endpoint both ways:

Bearer | correctly blocked:

Authorization: Bearer &lt;token&gt;
PATCH /api/v1/user/settings  -&gt;  403 Forbidden

Basic | bypass:

Authorization: Basic base64(&lt;token&gt;:x-oauth-basic)
PATCH /api/v1/user/settings  -&gt;  200 OK

All verified bypass endpoints using a read:user-only token:

| Endpoint | Bearer | Basic | |---|---|---| | PATCH /api/v1/user/settings | 403 | 200 | | POST /api/v1/user/emails | 403 | 200 | | POST /api/v1/user/repos | 403 | 200 | | PATCH /api/v1/repos/{owner}/{repo} | 403 | 200 | | DELETE /api/v1/repos/{owner}/{repo} | 403 | 200 |

The bypass respects the user's normal repository permissions, it does not grant access to repositories the user cannot otherwise reach, and does not escalate to admin.

Impact

Any OAuth2 application with any restricted scope can silently operate beyond its granted permissions by switching from Bearer to Basic auth. An attacker who obtains a token (e.g. via a malicious OAuth2 app a user authorized) can:

Modify the victim's profile and settings
Add attacker-controlled email addresses to the victim's account
Create repositories as the victim
Modify or delete the victim's private repositories

The entire OAuth2 scope system is effectively bypassed for any token submitted via Basic auth.

Published: Jun 16, 2026
Updated: Jun 17, 2026
CVE: CVE-2026-28699
GHSA: GHSA-9r5x-wg6m-x2rc
Severity: High
Exploit:
CISA KEV:

CVSS v3:

Severity: High
Score: 8.1
AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N

CWEs:

OWASP TOP 10:

A5 - Broken Access Control

Affected Software
References

Software	From	Fixed in
code.gitea.io/gitea	-	1.26.2

https://github.com/go-gitea/gitea/security/advisories/GHSA-9r5x-wg6m-x2rc

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Frequently Asked Questions

What is a Vulnerability (CVE) and why does it matter?

A security vulnerability is a weakness in software, hardware, or configuration that can be exploited to compromise confidentiality, integrity, or availability. Many vulnerabilities are tracked as CVEs (Common Vulnerabilities and Exposures), which provide a standardized identifier so teams can coordinate patching, mitigation, and risk assessment across tools and vendors.

CVSS (Common Vulnerability Scoring System) estimates technical severity, but it doesn't automatically equal business risk. Prioritize using context like internet exposure, affected asset criticality, known exploitation (proof-of-concept or in-the-wild), and whether compensating controls exist. A "Medium" CVSS on an exposed, production system can be more urgent than a "Critical" on an isolated, non-production host.

A vulnerability is the underlying weakness. An exploit is the method or code used to take advantage of it. A zero-day is a vulnerability that is unknown to the vendor or has no publicly available fix when attackers begin using it. In practice, risk increases sharply when exploitation becomes reliable or widespread.

Recurring findings usually come from incomplete Asset Discovery, inconsistent patch management, inherited images, and configuration drift. In modern environments, you also need to watch the software supply chain: dependencies, containers, build pipelines, and third-party services can reintroduce the same weakness even after you patch a single host. Unknown or unmanaged assets (often called Shadow IT) are a common reason the same issues resurface.

Use a simple, repeatable triage model: focus first on externally exposed assets, high-value systems (identity, VPN, email, production), vulnerabilities with known exploits, and issues that enable remote code execution or privilege escalation. Then enforce patch SLAs and track progress using consistent metrics so remediation is steady, not reactive.

SynScan combines attack surface monitoring and continuous security auditing to keep your inventory current, flag high-impact vulnerabilities early, and help you turn raw findings into a practical remediation plan.