TinaCMS @tinacms/mdx: Code injection via MDX serializer rich-text values
Summary
The MDX serializer of the @tinacms/mdx package writes rich-text values into MDX expressions without escaping them. An authenticated content editor can save crafted values that break out of list field or highlightColor expressions in the stored .mdx file. The injected JavaScript can then run in visitors' browsers or on build and server-side rendering hosts.
Affected
- @tinacms/mdx versions before 2.4.2 (affected range: 0 to before 2.4.2)
Fixed in
- Fixed in @tinacms/mdx 2.4.2
Workaround
- No vendor workaround known. Unknown.
Exploitation
- Not known to be exploited in the wild.
- No public exploit code indexed in Metasploit or Exploit-DB.
Our recommendation
- Upgrade @tinacms/mdx to 2.4.2 or later, and review the whole Tina stack for updates.
- Until the upgrade, limit content editor accounts to trusted users, especially contractors and agencies.
- Review stored .mdx files for unexpected content before the next build.
- Monitor build and deployment hosts for unusual activity.
Public exploits
PoC-in-GitHub, Metasploit and Exploit-DB list nothing for this CVE.
Research sources
- GitHub Security Advisory GHSA-6vw5-w22x-ghxv github.com
- TinaCMS release @tinacms/mdx 2.4.2 github.com
- Fix commit 19285c6 github.com
- Pull request #7958 github.com
- VulnCheck advisory www.vulncheck.com
- CVE-2026-126774 aggregator record cve.threatint.com
Researched and written up in English and German by an AI (Claude by Anthropic) based on NVD, CISA, EPSS and the sources listed. The vendor information is authoritative. Researched on 11 Nov 2026, 20:22.
Original description (NVD)
@tinacms/mdx before 2.4.2 contains a code injection vulnerability in its MDX serializer, which writes rich-text values into MDX expressions without escaping them. Authenticated content editors can save crafted values that break out of list field or highlightColor expressions in the stored .mdx file, executing JavaScript in visitors' browsers or on build and server-side rendering hosts.
NVD references (6)
- https://github.com/tinacms/tinacms/blob/%40tinacms/mdx%400.60.3/packages/%40tinacms/mdx/src/stringify/acorn.t…
- https://github.com/tinacms/tinacms/commit/19285c6deeee52c380e8b2fdeafedc9530dc0618
- https://github.com/tinacms/tinacms/pull/7958
- https://github.com/tinacms/tinacms/releases/tag/%40tinacms/mdx%402.4.2
- https://github.com/tinacms/tinacms/security/advisories/GHSA-6vw5-w22x-ghxv
- https://www.vulncheck.com/advisories/tinacms-mdx-before-2.4.2-code-injection-via-mdx-serializer-rich-text-val…
Sources
The tracker combines official, freely usable data sources – updated continuously:
- NVD (NIST) – CVEs, rating (CVSS), affected products
- CISA KEV – vulnerabilities confirmed by CISA as actively exploited
- CISA Vulnrichment – CISA assessment (SSVC) in the official CVE record
- FIRST EPSS – probability of exploitation
- Microsoft MSRC – Patch Tuesday: vulnerabilities, severity, updates
- PoC-in-GitHub – public proof-of-concept repositories
- Metasploit (Rapid7) – modules of the Metasploit Framework
- Exploit-DB (OffSec) – archive of public exploits (links only)
- Patch days: official vendor pages (linked per vendor) (Vendor patch days)
This product uses data from the NVD API but is not endorsed or certified by the NVD. EPSS data © FIRST.org.
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