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CVE-2026-23603 low CVSS 3.1

SSRF (Server-Side Request Forgery) in code.gitea.io/gitea (CVE-2026-23603)

Summary

SSRF in code.gitea.io/gitea (CVE-2026-23603). Risk of unauthorized operations or information disclosure. Exploitable via picture. Mitigation: upgrade to 1.27.0 or later.

Original description

The description as published by the source.

Summary

When [oauth2_client] UPDATE_AVATAR = true is enabled, Gitea fetches the avatar URL received from an OAuth2/OIDC provider using Go's default HTTP client. The URL comes from the user's OAuth/OIDC avatar value, commonly the OIDC picture claim.

The affected code path calls http.Get(url) without applying outbound host or IP restrictions. A low-privileged user who can influence their own picture claim under an already-configured OAuth2/OIDC source can cause the Gitea server to make arbitrary outbound HTTP GET requests. This includes requests to loopback addresses, RFC 1918 private network addresses, and IPv4 link-local addresses such as 169.254.169.254.

This is a blind SSRF by default. Impact can increase in deployments where the Gitea host can reach cloud metadata services, localhost-only services, or internal services that return valid image data.

Details

The vulnerable sink is in routers/web/auth/oauth.go:

func oauth2UpdateAvatarIfNeed(ctx *context.Context, url string, u *user_model.User) {
    if setting.OAuth2Client.UpdateAvatar && len(url) > 0 {
        resp, err := http.Get(url)
        if err == nil {
            defer func() { _ = resp.Body.Close() }()
        }
        if err == nil && resp.StatusCode == http.StatusOK {
            data, err := io.ReadAll(io.LimitReader(resp.Body, setting.Avatar.MaxFileSize+1))
            if err == nil && int64(len(data)) <= setting.Avatar.MaxFileSize {
                _ = user_service.UploadAvatar(c…

Source: GitHub Security Advisories (Global) NVD GitHub Advisory

Auto-generated summary

Assembled by SecPulse from the source data (CVSS, CWE, affected versions) using templates — no AI involved. Check the original description and references below for exact details.

A vulnerability tracked as CVE-2026-23603 has been found in code.gitea.io/gitea.
Attackers can target a specific entry point like picture over the network to misuse the product.
Risk of unauthorized operations or information disclosure. CVSS score: 3.1/10.
What to do: upgrade code.gitea.io/gitea to 1.27.0 or later.
If unsure, ask your IT team or search "code.gitea.io/gitea CVE-2026-23603" on the vendor's site.

CVE-2026-23603 (code.gitea.io/gitea) — CWE-918 / CVSS v3 3.1
Attack vector: remote (network-reachable) / no user interaction
Attack surface: picture / gothUser.AvatarURL / http.Get / hostmatcher.NewDialContext
Patched: 1.27.0 — apply immediately
Plan: 1) Audit SBOM/dependencies, 2) Stage→prod upgrade, 3) Add WAF/proxy monitoring on affected endpoints, 4) Hunt IOCs in logs.
Refs: see the GHSA / vendor advisory / patched release linked on this page.

❓ What is the problem

SSRF (CWE-918) exists in code.gitea.io/gitea. Attackers reach the vulnerable code path via picture.

📍 Affected scope

Check the vendor advisory for the affected versions of code.gitea.io/gitea. Attack surface: picture / gothUser.AvatarURL / http.Get / hostmatcher.NewDialContext.

🔥 Severity

Severity: Low (CVSS 3.1/10). Risk of unauthorized operations or information disclosure.

🔧 How to fix

Update to 1.27.0.

🛡️ Workaround

Until the patch is applied: disable the affected feature, apply WAF rules, or restrict access via network ACLs.

🔍 Detection

Search webserver/proxy logs for unusual request patterns matching this CVE's known IOCs. Run grep -r 'code.gitea.io/gitea' . against your dependency files (package-lock.json, requirements.txt, go.sum) to find affected services.

Response actions

Concrete steps and command examples for SOC/SRE teams to execute in order

  1. 1
    Identify exposure identify 
    grep -r 'code.gitea.io/gitea' . | grep -v node_modules

    リポジトリと本番環境の依存ファイル (package-lock.json / requirements.txt / go.sum / Gemfile.lock 等) で code.gitea.io/gitea を grep し、稼働しているサービス・バージョンを把握する。

  2. 2
    Apply patch patch 
    Upgrade code.gitea.io/gitea to 1.27.0

    ステージング環境で 1.27.0 に上げて回帰テスト → 本番反映。回帰テストはアプリの主要ハッピーパスを含めること。

  3. 3
    Post-deployment verification verify 
    Confirm patched version is live in production

    パッチ適用後、ステージングで PoC または同等の悪用パターンを再現して脆弱性が閉じたことを確認。本番ではアクセスログ・WAF でアラート再発が無いか継続監視。

Affected packages

go code.gitea.io/gitea
[{"type":"SEMVER","events":[{"introduced":"0"},{"fixed":"1.27.0"}]}]
Go gitea.dev
[{"type":"SEMVER","events":[{"introduced":"0"},{"fixed":"1.27.0"}]}]

References

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