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.
CVE-2026-55661
MEDIUMPre-NVD 4.84.8—Trending — 3 sources updated this week
EchelonGraph scoreMEDIUM confidence
This medium-severity CVE scores 4.8 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit probability: 0.2%, top 85% of all CVEs by exploit prediction. GitHub Security Advisory data not yet ingested — confidence will rise once GHSA publishes (typical lag: hours to days for open-source ecosystem CVEs; never for infrastructure-only CVEs).
Triggered by: NVD CVSS baseline
Sources: epss, secondary
4.8
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
- Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS: 0%CVSS: 4.8Exploit: NoneExposed: 0
No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.
- CVSS v3
- 4.8
- EG Score
- 4.8(medium)
- EPSS
- 14.9%
- KEV
- Not listed
Published
June 18, 2026
Last Modified
July 6, 2026
Advisory Details (2)
Auto-updated Jul 5, 2026🔬 Proof of concept available. Patch available. Sources: github_pr, github.
github Patch Available🟡 PoC Available
TinaCMS rich-text (slatejson) rendering does not sanitize link/image URLs, allowing stored XSS via dangerous URL schemes · Advisory · tinacms/tinacms · GitHub
https://github.com/tinacms/tinacms/security/advisories/GHSA-2vcc-5v34-9jc8github_pr Patch Available
Harden message origin checks and rich-text URL sanitization
Patch available: tinacms/tinacms [email protected] (PR #7056 merged 2026-06-15)
https://github.com/tinacms/tinacms/pull/7056Vendor Advisories for CVE-2026-55661(1)
These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.
Affected Packages
(2 across 1 ecosystem)
npm(2)
| Package | Vulnerable range | Fixed in | Dependents |
|---|---|---|---|
| tinacms | — | 3.9.3 | — |
| @tinacms/mdx | — | 2.1.7 | — |
Weakness Classification(2)
MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.
Data Freshness Timeline
(refreshed 14× in last 7d / 15× in last 30d)
Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.
- 2026-07-06 16:27 UTCEPSS rescore
- 2026-07-06 16:27 UTCEPSS rescore
- 2026-07-06 09:56 UTCEG score recompute
- 2026-07-06 02:23 UTCEPSS rescore
- 2026-07-06 02:23 UTCEPSS rescore
- 2026-07-05 06:58 UTCEG score recompute
- 2026-07-05 02:31 UTCEPSS rescore
- 2026-07-05 02:30 UTCEPSS rescore
- 2026-07-04 06:31 UTCEPSS rescore
- 2026-07-04 06:31 UTCEPSS rescore
- 2026-07-04 04:37 UTCEG score recompute
- 2026-07-03 01:26 UTCEG score recompute
- 2026-07-01 23:10 UTCEG score recompute▲ 4.80
- 2026-07-01 23:08 UTCNVD updateCVSS v3 → 4.8 · CVSS v4 → 4.8
- 2026-06-18 13:45 UTCEG score recompute
Related CVEs(same CWE)
Frequently asked(5)
What is CVE-2026-55661?
CVE-2026-55661 is a medium vulnerability published on June 18, 2026. 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,…
When was CVE-2026-55661 disclosed?
CVE-2026-55661 was first published in the National Vulnerability Database on June 18, 2026, with the most recent update on July 6, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-55661 actively exploited?
CVE-2026-55661 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 14.9% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.
What is the CVSS score of CVE-2026-55661?
CVE-2026-55661 has a CVSS v3 base score of 4.8 (NVD).
How do I remediate CVE-2026-55661?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-55661, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.
Dependency Blast Radius
See which npm, PyPI, Go, and Maven packages are affected by CVE-2026-55661
Is Your Infrastructure Affected by CVE-2026-55661?
EchelonGraph automatically scans your cloud infrastructure and maps CVE exposure using blast radius analysis.