Cross-Site Scripting (XSS) in tinacms (CVE-2026-55661)
Summary
Cross-site scripting in tinacms (CVE-2026-55661). Risk of unauthorized operations or information disclosure. Exploitable via url. Mitigation: upgrade to 3.9.3 or later.
Original description
The description as published by the source.
Tina is a headless content management system. In versions prior to @tinacms/mdx 2.1.7 and tinacms 3.9.3, rich-text parsing and the default link/image renderers did not sanitize the url field on Slate link/image nodes. Content containing javascript: or data:text/html URLs — including case-variant, whitespace-padded, and control-character-obfuscated forms — is rendered into href/src and executes when the content is viewed. Any actor able to author rich-text content (for example a lower-privileged editor, or imported/external content) can achieve stored XSS against editors and site viewers. This issue is fixed in versions @tinacms/mdx 2.1.7 and tinacms 3.9.3.
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-2026-55661 has been found in tinacms.
Attackers can target a specific entry point like url over the network to misuse the product.
Risk of unauthorized operations or information disclosure.
What to do: upgrade tinacms to 3.9.3 or later.
If unsure, ask your IT team or search "tinacms CVE-2026-55661" on the vendor's site.
CVE-2026-55661 (tinacms) — CWE-79
Attack surface: url / href / src
Patched: 3.9.3 — 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 tinacms. Attackers reach the vulnerable code path via url.
Check the vendor advisory for the affected versions of tinacms. Attack surface: url / href / src.
Severity: ?. Risk of unauthorized operations or information disclosure.
Update to 3.9.3.
Until the patch is applied: disable the affected feature, apply WAF rules, or restrict access via network ACLs.
Search webserver/proxy logs for unusual request patterns matching this CVE's known IOCs. Run grep -r 'tinacms' . 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 'tinacms' . | 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
tinacmsを grep し、稼働しているサービス・バージョンを把握する。 -
2Apply patch patch
Upgrade tinacms to 3.9.3ステージング環境で 3.9.3 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を含めること。
-
3Post-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
References
- advisory github.com
- advisory github.com
- advisory nvd.nist.gov
- package github.com
- patch github.com
- web github.com