VulnerabilityPublished 21 Jul 2026

CVE-2026-56654: Gitea · Privilege Escalation via Access Token Scope Escalation in API

Affects code.gitea.io/giteaSource GCVE Database

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Authoritative record:CVE-2026-56654· Critical 9.8

Not known to be exploited · CVSS 9.8 Critical : upgrade to 1.27.0 as a priority.

Data as of 30 Oct 2026, 11:52 UTC

CVSS 3.1 base score

9.8Critical

How severe the flaw is on the 0–10 CVSS scale.

EPSS: 0.8% chance of exploitation in 30 days – higher than 57% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch: Available – fixed in 1.27.0

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

Attack Vector: Network
Attack Complexity: Low
Privileges Required: None
User Interaction: None
Scope: Unchanged
Confidentiality: High
Integrity: High
Availability: High

Bold values are the worst case: easiest to exploit or largest impact.

Attack Vector: Network: The vulnerable component is bound to the network stack and the set of possible attackers extends beyond the other options listed, up to and including the entire Internet. Such a vulnerability is often termed 'remotely exploitable' and can be thought of as an attack being exploitable at the protocol level one or more network hops away (e.g., across one or more routers).
Attack Complexity: Low: Specialized access conditions or extenuating circumstances do not exist. An attacker can expect repeatable success against the vulnerable component.
Privileges Required: None: The attacker is unauthorized prior to attack, and therefore does not require any access to settings or files to carry out an attack.
User Interaction: None: The vulnerable system can be exploited without any interaction from any user.
Scope: Unchanged: An exploited vulnerability can only affect resources managed by the same security authority. In this case, the vulnerable component and the impacted component are either the same, or both are managed by the same security authority.
Confidentiality: High: There is total loss of confidentiality, resulting in all resources within the impacted component being divulged to the attacker. Alternatively, access to only some restricted information is obtained, but the disclosed information presents a direct, serious impact.
Integrity: High: There is a total loss of integrity, or a complete loss of protection. For example, the attacker is able to modify any/all files protected by the impacted component. Alternatively, only some files can be modified, but malicious modification would present a direct, serious consequence to the impacted component.
Availability: High: There is total loss of availability, resulting in the attacker being able to fully deny access to resources in the impacted component; this loss is either sustained (while the attacker continues to deliver the attack) or persistent (the condition persists even after the attack has completed). Alternatively, the attacker has the ability to deny some availability, but the loss of availability presents a direct, serious consequence to the impacted component (e.g., the attacker cannot disrupt existing connections, but can prevent new connections; the attacker can repeatedly exploit a vulnerability that, in each instance of a successful attack, leaks a only small amount of memory, but after repeated exploitation causes a service to become completely unavailable).

Definitions: FIRST CVSS v3.1 specification.

Exploitation evidence

t = 0 is the CVE’s publication on cve.org

Disclosed: evidence found.
CVE published 13 Aug 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: evidence found.
CISA SSVC: proof of concept public
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors

CVE ID reserved
by Gitea Limited
8 Jul 202609:19 UTC, 36 days before disclosure
CVE published
on cve.org
13 Aug 202616:44 UTC, t = 0
CISA SSVC assessment
proof of concept public
14 Aug 202619:19 UTC, 27 hours after disclosure

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), CISA SSVC, the Metasploit, Exploit-DB and nuclei-templates index as of 30 Oct 2026.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponized: A Metasploit exploit module or Exploit-DB entry exists (Metasploit scanner modules do not count), or CISA SSVC or the CVSS exploit maturity reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

What to do

Upgrade code.gitea.io/gitea to 1.27.0.

Affected software

Product	Affected	Fixed in
Gocode.gitea.io/gitea	Affected <1.27.0	Fixed in 1.27.0

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

Description

Gitea's API endpoint for creating Personal Access Tokens (`POST /users/{username}/tokens`) is protected by a middleware (`reqBasicOrRevProxyAuth`) that is intended to require password-based authentication, preventing a compromised token from being used to mint new ones. However, when a token is passed in the `Authorization: Basic <token>:x-oauth-basic` format, the Basic auth handler validates it and sets `AuthedMethod="basic"`, causing `IsBasicAuth=true` and fooling the middleware into passing the request. Once past the guard, the token creation handler applies no scope ceiling — it will create a new token with any requested scope regardless of the caller's scope. An attacker with a restricted token (e.g. `write:user` from a leaked CI secret) can therefore create a fully-privileged `all`-scoped token without knowing the account password. ### Data flow #### Step 1 - Token extracted from Basic auth header When the attacker sends Authorization: Basic base64(<token>:x-oauth-basic), parseAuthBasic detects that the password is "x-oauth-basic" and treats the username field as the token: https://github.com/go-gitea/gitea/blob/9155a81b9daf1d46b2380aa91271e623ac947c1e/services/auth/basic.go#L55-L64 `VerifyAuthToken` then validates the token against the database and sets `LoginMethod = "access_token"` and `ApiTokenScope` to the token's actual scope (`write:user`): https://github.com/go-gitea/gitea/blob/9155a81b9daf1d46b2380aa91271e623ac947c1e/services/auth/basic.go#L100-L106 #### Step 2 - `AuthedMethod` is set to `"basic"`, not `"access_token"` `Basic.Verify()` returns the user successfully, so `group.Verify()` sets `AuthedMethod` to the method's name — `"basic"` — regardless of whether a password or token was used: https://github.com/go-gitea/gitea/blob/9155a81b9daf1d46b2380aa91271e623ac947c1e/services/auth/group.go#L63-L65 #### Step 3 - `IsBasicAuth` is incorrectly set to true `AuthShared` computes `IsBasicAuth` by comparing `AuthedMethod` against the constant `"basic"`. Since step 2 set that field to "basic" for a token-authenticated request, the flag is wrong: https://github.com/go-gitea/gitea/blob/9155a81b9daf1d46b2380aa91271e623ac947c1e/routers/common/auth.go#L27 #### Step 4 - The guard is bypassed `reqBasicOrRevProxyAuth` checks only `ctx.IsBasicAuth`. Because that flag is `true`, the middleware passes and the request reaches `CreateAccessToken`: https://github.com/go-gitea/gitea/blob/9155a81b9daf1d46b2380aa91271e623ac947c1e/routers/api/v1/api.go#L392-L401 #### Step 5 - No scope ceiling in the handler `CreateAccessToken` normalizes the caller-supplied scope and assigns it directly to the new token. There is no check that the requested scope is a subset of `ApiTokenScope (write:user)`: https://github.com/go-gitea/gitea/blob/9155a81b9daf1d46b2380aa91271e623ac947c1e/routers/api/v1/user/app.go#L119-L128 ### Reproducing `tests/integration/api_token_scope_escalation_test.go` ```go package integration import ( "net/http" "testing" auth_model "gitea.dev/models/auth" "gitea.dev/models/unittest" user_model "gitea.dev/models/user" api "gitea.dev/modules/structs" "gitea.dev/tests" "github.com/stretchr/testify/assert" "github.com/stretchr/testify/require" ) // TestAPIPrivilegeEscalationViaBasicAuthToken is a proof-of-concept for two // interconnected vulnerabilities that together allow full scope escalation: // // 1. reqBasicOrRevProxyAuth() is fooled into passing when a PAT is supplied in // the Authorization: Basic "<token>:x-oauth-basic" format. The Basic auth // handler sets AuthedMethod="basic" (the method name), so IsBasicAuth=true // even though the credential is a token, not a password. // // 2. CreateAccessToken performs no scope-ceiling check — it never verifies that // the requested scopes are a subset of the caller's token scopes. // // Combined effect: an attacker with a write:user-scoped token can create a new // token with the "all" scope, gaining full access to the account. func TestAPIPrivilegeEscalationViaBasicAuthToken(t *testing.T) { defer tests.PrepareTestEnv(t)() // Non-admin user — escalation is meaningful and not trivially justified. user := unittest.AssertExistsAndLoadBean(t, &user_model.User{ID: 2}) // Step 1 — Obtain a legitimately restricted token via password-based Basic auth. // Only write:user scope is granted; repository, admin, etc. are excluded. restrictedToken := createAPIAccessTokenWithoutCleanUp(t, "poc-restricted", user, []auth_model.AccessTokenScope{auth_model.AccessTokenScopeWriteUser}) defer deleteAPIAccessToken(t, restrictedToken, user) // Confirm the restricted token is blocked from repository-scoped endpoints. // This establishes the baseline: write:user does not imply read:repository. req := NewRequest(t, "GET", "/api/v1/repos/search"). AddTokenAuth(restrictedToken.Token) MakeRequest(t, req, http.StatusForbidden) // Step 2 — Exploit: supply the restricted token as Basic auth credentials. // Authorization: B

CWE-287Improper Authentication (opens in a new tab)
Class weaknessLikelihood of exploit: HighOWASP Top 10 A07:2025: Authentication Failures (opens in a new tab)
When an actor claims to have a given identity, the product does not prove or insufficiently proves that the claim is correct.
MITRE discourages mapping vulnerabilities to this broad entry; the root cause is usually a more specific weakness.
Architecture and Design · Libraries or Frameworks
Use an authentication framework or library such as the OWASP ESAPI Authentication feature.
OWASP Cheat Sheets
OWASP Authentication (opens in a new tab)
OWASP ASVS 4.0.3
V2.8.5 (opens in a new tab)
V2.8.4 (opens in a new tab)
V9.2.3 (opens in a new tab)
Attack patterns
Fake the Source of Data (opens in a new tab)
Utilizing REST's Trust in the System Resource to Obtain Sensitive Data (opens in a new tab)
Session Hijacking (opens in a new tab)
Token Impersonation (opens in a new tab)
Upload a Web Shell to a Web Server (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).

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Affected software

Description

WeaknessesCWE-287

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