CVE-2026-28699

Gitea versions up to and including 1.26.1 allow OAuth2 access token scope enforcement to be bypassed through HTTP Basic authentication.

Gitea versions up to and including 1.26.1 allow OAuth2 access token scope enforcement to be bypassed through HTTP Basic authentication.

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()["LoginMethod"] = OAuth2TokenMethodName
    store.GetData()["IsApiToken"] = 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["ApiTokenScope"].(auth_model.AccessTokenScope)
if ctx.Data["IsApiToken"] != true || !scopeExists {
    return   //<- 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

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

Bearer | correctly blocked:

Authorization: Bearer <token>
PATCH /api/v1/user/settings  ->  403 Forbidden

Basic | bypass:

Authorization: Basic base64(<token>:x-oauth-basic)
PATCH /api/v1/user/settings  ->  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.

Gitea versions up to and including 1.26.1 allow OAuth2 access token scope enforcement to be bypassed through HTTP Basic authentication.

Gitea versions up to and including 1.26.1 allow OAuth2 access token scope enforcement to be bypassed through HTTP Basic authentication.

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()["LoginMethod"] = OAuth2TokenMethodName
    store.GetData()["IsApiToken"] = 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["ApiTokenScope"].(auth_model.AccessTokenScope)
if ctx.Data["IsApiToken"] != true || !scopeExists {
    return   //<- 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

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

Bearer | correctly blocked:

Authorization: Bearer <token>
PATCH /api/v1/user/settings  ->  403 Forbidden

Basic | bypass:

Authorization: Basic base64(<token>:x-oauth-basic)
PATCH /api/v1/user/settings  ->  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.

Gitea: OAuth2 access token scope enforcement bypass via HTTP Basic authentication in code.gitea.io/gitea

This update for govulncheck-vulndb fixes the following issues:

• Update to version 0.0.20260723T184607 2026-07-23T18:46:07Z (jsc#PED-11136).

Go CVE Numbering Authority IDs added or updated with aliases:

• GO-2026-4730 CVE-2026-33022 GHSA-cv4x-93xx-wgfj
• GO-2026-4761 CVE-2026-33211 GHSA-j5q5-j9gm-2w5c
• GO-2026-5102 CVE-2026-45021 GHSA-3vcp-chfh-f6r2
• GO-2026-5272 CVE-2026-40938 GHSA-94jr-7pqp-xhcq
• GO-2026-5486 CVE-2026-40924 GHSA-m2cx-gpqf-qf74
• GO-2026-5542 CVE-2026-40090 GHSA-pj97-4p9w-gx3q
• GO-2026-5630 CVE-2026-25542 GHSA-rmx9-2pp3-xhcr
• GO-2026-5643 CVE-2026-40923 GHSA-rx35-6rhx-7858
• GO-2026-5675 CVE-2026-41492 GHSA-vvf7-6rmr-m29q
• GO-2026-5711 CVE-2026-40161 GHSA-wjxp-xrpv-xpff
• GO-2026-5746 CVE-2026-41567 GHSA-x86f-5xw2-fm2r
• GO-2026-5749 CVE-2026-41328 GHSA-x92x-px7w-4gx4
• GO-2026-5837 CVE-2026-44840 GHSA-q2m9-6jp9-c6mc
• GO-2026-5929 CVE-2026-44342 GHSA-26v7-h57m-gh9m
• GO-2026-5930 CVE-2026-33655 GHSA-6qcr-qxgr-m7fv
• GO-2026-5933 GHSA-3g4q-2f67-2gvh
• GO-2026-5934 GHSA-59qp-cfj3-rp64
• GO-2026-5935 GHSA-7856-g3gv-9wq8
• GO-2026-5936 CVE-2026-53552 GHSA-26rh-24rg-j3vv
• GO-2026-5937 CVE-2026-53508 GHSA-2jcc-mxv7-p3f9
• GO-2026-5938 CVE-2026-53553 GHSA-4g5x-hcwm-82jw
• GO-2026-5939 CVE-2026-10517 GHSA-698x-9w2p-7vvp
• GO-2026-5940 CVE-2026-53572 GHSA-6w3m-4hhp-775q
• GO-2026-5941 CVE-2026-53487 GHSA-gvhc-wv3v-7pf8
• GO-2026-5942 CVE-2026-46600
• GO-2026-5944 CVE-2026-50197 GHSA-659f-rgp5-w4wf
• GO-2026-5945 CVE-2026-6815 GHSA-rmxx-v9rj-vpvg
• GO-2026-5946 CVE-2026-52831 GHSA-v5px-423j-pf7p
• GO-2026-5947 CVE-2026-53649 GHSA-xqhv-chqm-fhcc
• GO-2026-5948 CVE-2026-50554 GHSA-588f-fvcv-xhvf
• GO-2026-5949 CVE-2026-50553 GHSA-rqrh-8wpv-x7hh
• GO-2026-5950 CVE-2026-53602 GHSA-339v-266x-79xr
• GO-2026-5951 CVE-2026-10219 GHSA-6jm8-4fhr-5w64
• GO-2026-5952 CVE-2026-49834 GHSA-9vcr-p3rj-q5q6
• GO-2026-5953 CVE-2026-9094 GHSA-c9w5-qp6m-m395
• GO-2026-5956 CVE-2026-55252 GHSA-h5g6-xmh4-hc37
• GO-2026-5957 CVE-2026-54158 GHSA-5xfx-xj4h-5p7r
• GO-2026-5958 CVE-2026-54068 GHSA-gcm7-57gf-953c
• GO-2026-5959 CVE-2026-54072 GHSA-h29v-hj44-q8cv
• GO-2026-5961 CVE-2026-54069 GHSA-hvr9-72v2-fff3
• GO-2026-5962 CVE-2026-54088 GHSA-m93h-4hw7-5qcm
• GO-2026-5963 CVE-2026-54067 GHSA-mvjr-vv3c-w4qv
• GO-2026-5964 CVE-2026-54066 GHSA-p4m3-mgmm-c664
• GO-2026-5965 CVE-2026-54070 GHSA-w7cg-whh7-xp28
• GO-2026-5966 CVE-2026-54089 GHSA-xqp3-jq6g-x3qm
• GO-2026-5967 CVE-2026-50551 GHSA-56mp-4f3v-fgj2
• GO-2026-5968 CVE-2026-54174 GHSA-fpg8-7664-jc5q
• GO-2026-5969 GHSA-g936-7jqj-mwv8
• GO-2026-5970 CVE-2026-56852
• GO-2026-5973 CVE-2026-54250 GHSA-jxr7-mqhw-9p98
• GO-2026-5974 CVE-2026-44300 GHSA-wmj8-9953-vff5
• GO-2026-5975 CVE-2026-50018 GHSA-42j2-w334-qxw7
• GO-2026-5976 CVE-2026-50141 GHSA-g7mm-9vx7-jm7h
• GO-2026-5977 CVE-2026-50013 GHSA-qrh4-p6v4-mrfg
• GO-2026-5978 CVE-2026-50125 GHSA-qw5r-ppcg-f8rj
• GO-2026-5979 CVE-2026-50006 GHSA-xrcf-6jh3-ggvx
• GO-2026-5980 CVE-2026-50158 GHSA-2c7f-fxww-6w6c
• GO-2026-5981 GHSA-mqxv-9rm6-w8qc
• GO-2026-5982 GHSA-pqg7-v6wh-3pfp
• GO-2026-5984 CVE-2026-53604 GHSA-2p2f-px33-4vv5
• GO-2026-5985 GHSA-7rx3-5wx3-5v76
• GO-2026-5986 CVE-2026-61699 GHSA-cm26-5974-52h8
• GO-2026-5987 CVE-2026-55513 GHSA-g4x6-jcvr-9m3g
• GO-2026-5988 CVE-2026-54628 GHSA-hwrq-8wxh-q4xv
• GO-2026-5989 CVE-2026-55512 GHSA-m3cx-mwpg-32jg
• GO-2026-5990 CVE-2026-54629 GHSA-mf78-3rpf-r784
• GO-2026-5991 CVE-2026-53603 GHSA-q4vm-pq3q-8wgq
• GO-2026-5992 CVE-2026-61549 GHSA-qf34-295c-26v8
• GO-2026-5996 CVE-2026-54450 GHSA-pph6-vfjv-vpjw
• GO-2026-5997 CVE-2026-54452 GHSA-xgch-x3mx-cm3c
• GO-2026-5998 CVE-2026-54495 GHSA-398h-7f66-3h4p
• GO-2026-5999 CVE-2026-10814 GHSA-jh6h-v6mp-h22v
• GO-2026-6002 CVE-2026-58196 GHSA-pr64-jmmf-jp54
• GO-2026-6003 CVE-2026-53714 GHSA-22xc-xg2r-9j7v
• GO-2026-6004 CVE-2026-52833 GHSA-3v79-m2cg-89ww
• GO-2026-6005 CVE-2026-53715 GHSA-8fv2-88gg-hm7q
• GO-2026-6006 CVE-2026-53716 GHSA-cxpq-8v7q-cg56 *…