CVE-2026-55661
CVE-2026-55661 is a medium-severity vulnerability with a CVSS 4.0 base score of 4.8. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-79.
Key facts
- Severity: Medium (CVSS 4.0 base score 4.8)
- EPSS exploit prediction: 0% (15th percentile)
- Actively exploited: Not listed in CISA KEV
- Weakness: CWE-79
- Published:
- Last modified:
Description
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.
Frequently asked questions
- What is CVE-2026-55661?
- 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.
- How severe is CVE-2026-55661?
- CVE-2026-55661 has a CVSS 4.0 base score of 4.8, rated medium severity.
- Is CVE-2026-55661 being actively exploited?
- It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (15th percentile), an estimate of the probability of exploitation in the next 30 days.
- How do I fix CVE-2026-55661?
- Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
- When was CVE-2026-55661 published?
- CVE-2026-55661 was published on 2026-07-01 and last updated on 2026-07-06.
References
- https://github.com/tinacms/tinacms/pull/7056
- https://github.com/tinacms/tinacms/security/advisories/GHSA-2vcc-5v34-9jc8
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