Vulnerability record
CVE-2026-126774
The short answer
CVE-2026-126774 affects tinacms @tinacms/mdx and is rated high (CVSS 8.8). It is not in CISA's Known Exploited Vulnerabilities catalog.
What it is
@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.
Weakness: CWE-94.
Severity
8.8 high
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
Exploited (CISA KEV)
Not listed
CISA lists confirmed exploitation only
EPSS, next 30 days
No score
FIRST scores CVEs within a day of publication
How it can be exploited
- Attack vector
- Network
- Attack complexity
- Low
- Attack requirements
- Present
- Privileges required
- Low
- User interaction
- None
- Confidentiality impact
- High
- Integrity impact
- High
- Availability impact
- None
Affected products
@tinacms/mdx. NVD's record lists the exact affected versions.
References
- github.com/tinacms/tinacms/blob/%40tinacms/mdx%400.60.3/packages/%40tinacms/mdx/src/stringify/acorn.ts#L81
- github.com/tinacms/tinacms/commit/19285c6deeee52c380e8b2fdeafedc9530dc0618
- github.com/tinacms/tinacms/pull/7958
- github.com/tinacms/tinacms/releases/tag/%40tinacms/mdx%402.4.2
- github.com/tinacms/tinacms/security/advisories/GHSA-6vw5-w22x-ghxv
- www.vulncheck.com/advisories/tinacms-mdx-before-2.4.2-code-injection-via-mdx-serializer-rich-text-values
Questions
Is CVE-2026-126774 being exploited?
It is not in CISA's Known Exploited Vulnerabilities catalog as of 2026-11-12.
How do I fix CVE-2026-126774?
Follow the vendor advisory in the references below. NVD lists the affected versions under its configurations.
From NVD, CISA KEV, FIRST EPSS and OSV.dev, checked . Status on NVD: Received. The description is NVD's text, quoted as published.
Related
Know the day a CVE lands in your code
Connect a GitHub repository and ZeusQA checks its dependencies daily, briefs each advisory and opens the fix. Three test runs free, no card.