CVE-2026-126774 json
@tinacms/mdx before 2.4.2 Code Injection via MDX Serializer Rich-Text Values
published 9d ago modified 15h ago also GHSA-6vw5-w22x-ghxv , EUVD-2026-123768
Unreviewed: the maintainers' own advisory
Published by the maintainers on their GitHub repository tinacms/tinacms. GitHub has not reviewed it into the GitHub Advisory Database, so the affected packages and versions are the maintainers' word. Read the full advisory on GitHub.
- cvss
- 8.2
- version 3.1, CNA
- cisa kev
- Not listed
- not in CISA's catalog
- epss
- —
- no EPSS score yet
- public exploits
- 0
- none known
Summary
@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.
Patch / fix
- npm @tinacms/mdx 2.4.2
- tinacms @tinacms/mdx 2.4.2
Is CVE-2026-126774 in your dependencies? Fencer shows which of your repositories are affected as soon as an advisory lands, and opens the fix as a pull request.
Check with FencerCVSS scores
| assigned by | version | score | vector |
|---|---|---|---|
| CNA | 4.0 | 8.8 | CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:H/VI:H/VA:N/SC:H/SI:H/SA:N |
| CNA | 3.1 | 8.2 | CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:N |
| CNA | 4.0 | 8.8 | CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:H/VI:H/VA:N/SC:H/SI:H/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X |
| NVD | 3.1 | 8.2 | CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:N |
Affected packages
| ecosystem | package | affected | fixed in |
|---|---|---|---|
| npm | @tinacms/mdx | <2.4.2 |
2.4.2 |
Affected products
- tinacms @tinacms/mdx
Classification
- Weakness
-
- CWE-94 Improper Control of Generation of Code
References
-
github.com
/tinacms/tinacms/pull/7958
patch, issue-tracking
-
github.com
/tinacms/tinacms/commit/19285c6deeee52c380e8b2fdeafedc9530dc0618
patch
-
github.com
/tinacms/tinacms/security/advisories/GHSA-6vw5-w22x-ghxv
vendor-advisory, advisory
-
github.com
/tinacms/tinacms/releases/tag/%40tinacms/mdx%402.4.2
release-notes
-
github.com
/tinacms/tinacms/blob/%40tinacms/mdx%400.60.3/packages/%40tinacms/mdx/src/stringify/acorn.ts#L81
technical-description
-
vulncheck.com
/advisories/tinacms-mdx-before-2.4.2-code-injection-via-mdx-serializer-rich-text-values
third-party-advisory
Sources
- CVE List CVE-2026-126774
- NVD CVE-2026-126774
- Maintainer advisory GHSA-6vw5-w22x-ghxv
Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.
The maintainers of tinacms/tinacms published their own advisory on GitHub. Reviewed sources take precedence over it.