Cross-Site Scripting (XSS) in gogs.io/gogs (CVE-2026-52816)
Summary
Cross-site scripting in gogs.io/gogs (CVE-2026-52816). Risk of unauthorized operations or information disclosure. Exploitable via POST /-/api/sanitize_ipynb. Mitigation: upgrade to 0.14.3 or later.
Original description
The description as published by the source.
Gogs is an open source self-hosted Git service. Prior to 0.14.3, the Jupyter Notebook (ipynb) sanitizer endpoint at POST /-/api/sanitize_ipynb allows arbitrary data: URIs without proper restrictions, potentially leading to Cross-Site Scripting (XSS). The endpoint uses bluemonday.UGCPolicy() with p.AllowURLSchemes("data") which permits all data URI schemes including data:text/html, enabling attackers to inject malicious HTML/JavaScript. Additionally, the endpoint has no authentication middleware, allowing any registered user to exploit this vulnerability. This vulnerability is fixed in 0.14.3.
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-2026-52816 has been found in gogs.io/gogs.
Attackers can target a specific entry point like POST /-/api/sanitize_ipynb over the network to misuse the product.
Risk of unauthorized operations or information disclosure.
What to do: upgrade gogs.io/gogs to 0.14.3 or later.
If unsure, ask your IT team or search "gogs.io/gogs CVE-2026-52816" on the vendor's site.
CVE-2026-52816 (gogs.io/gogs) — CWE-79
Attack surface: POST /-/api/sanitize_ipynb / isSafeDataURI
Patched: 0.14.3 — 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.
Cross-site scripting (XSS) (CWE-79) exists in gogs.io/gogs. Attackers reach the vulnerable code path via POST /-/api/sanitize_ipynb.
Check the vendor advisory for the affected versions of gogs.io/gogs. Attack surface: POST /-/api/sanitize_ipynb / isSafeDataURI.
Severity: ?. Risk of unauthorized operations or information disclosure.
Update to 0.14.3.
Until the patch is applied: disable the affected feature, apply WAF rules, or restrict access via network ACLs.
Search webserver/proxy logs for unusual POST /-/api/sanitize_ipynb requests with malformed payloads or SQL meta-characters. Run grep -r 'gogs.io/gogs' . 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
-
1Identify exposure identify
grep -r 'gogs.io/gogs' . | 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
gogs.io/gogsを grep し、稼働しているサービス・バージョンを把握する。 -
2Hunt for indicators of compromise detect
grep 'POST /-/api/sanitize_ipynb' /var/log/nginx/access.log | grep -E '(unusual_payload|sqli_pattern)'アクセスログで
POST /-/api/sanitize_ipynbへの異常なリクエスト (不正な認証ヘッダ・SQLメタ文字)を過去 30〜90日分捜索。WAF/SIEM があれば該当パスのアラート発火履歴を確認。 -
3Apply patch patch
Upgrade gogs.io/gogs to 0.14.3ステージング環境で 0.14.3 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と、Step 2 で見つけた異常検知の続報チェックを含めること。
-
4Post-deployment verification verify
Replay attack against POST /-/api/sanitize_ipynb on staging to confirm patch closes the vector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 Step 2 と同じログクエリでアラート再発が無いか継続監視。
Affected packages
References
- advisory github.com
- advisory nvd.nist.gov
- advisory github.com
- package github.com
- patch github.com
- patch github.com
- web github.com
- web github.com