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CVE-2026-126774 @tinacms/mdx before 2.4.2 Code Injection via MDX Serializer Rich-Text Values

8.8 highEPSS 0.4%

High (8.8) in tinacms @tinacms/mdx. EPSS 0.4% estimated probability of exploitation activity in the next 30 days.

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@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.

Severity

CVSS 4.0

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

CVSS 3.1

8.2 high
CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:N
EPSS
0.4% estimated probability of exploitation activity in the next 30 days; 31st percentile. Scored 2026-11-13. A forecast for this CVE across the internet, not for your own systems.
CWE
CWE-94 Improper Control of Generation of Code (Code Injection)
OWASP Top 10
A05:2025 Injection
Published
Modified
Assigned by
VulnCheck (CNA)
NVD analysis
Awaiting analysis
Record from
the NVD, synced

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Affected

  • tinacms:@tinacms/mdx

Versions

From the CNA's record in the CVE List.

ProductAffected
tinacms @tinacms/mdxbefore 2.4.2

Attack patterns (CAPEC)

  • CAPEC-35 Leverage Executable Code in Non-Executable Files Likelihood: High · Severity: Very High
  • CAPEC-77 Manipulating User-Controlled Variables Likelihood: High · Severity: Very High
  • CAPEC-242 Code Injection Likelihood: High · Severity: High

The attack patterns MITRE's CAPEC relates to this record's weaknesses, as MITRE names them. Credits.

References

Check your stackJSON