tinacms

CVE-2026-108261: TinaCMS admin preview iframe loads an attacker-controlled origin from the URL fragment

Is it exploited?

Not on CISA's list. CISA has not added it to the Known Exploited Vulnerabilities catalog as of 28 Oct 2026. If CISA adds it, this page shows it as known exploited.

How likely is exploitation in the next 30 days?

0.2%

EPSS score, percentile 9.4 of all scored records. A probability estimated by FIRST, not a report of exploitation.

CISA's SSVC assessment in the CVE record lists exploitation as poc.

How severe?

9.3 Critical

CVSS v3.1 base score, given by the CNA

What should I do?

CISA has set no required action, because the vulnerability is not in KEV.

The CVE record links no vendor advisory, patch or mitigation.

Which versions are affected?

Affected

< 3.14.0
< 2.5.14

Versions by product

Source: CISA Known Exploited Vulnerabilities (KEV) catalog, 2026.10.28, as of 28 Oct 2026; FIRST Exploit Prediction Scoring System (EPSS), v2026.06.15, as of 29 Oct 2026; CVE List V5 (CVE Program), cve_2026-10-29_0000Z, as of 29 Oct 2026. About the data.

What to do

Advisories and patches

The CVE record links no vendor advisory, patch or mitigation.

Affected products and versions

As listed in the CVE record.

tinacms tinacms
Status	Versions
Affected	< 3.14.0

@tinacms app
Status	Versions
Affected	< 2.5.14

Source: CVE List V5 (CVE Program), cve_2026-10-29_0000Z, as of 29 Oct 2026. About the data.

About this vulnerability

Summary: CVE record, as of 29 Oct 2026.

CISA has not added CVE-2026-108261 to its Known Exploited Vulnerabilities (KEV) catalog, as of 28 Oct 2026.
The CVE record was published on 9 Oct 2026.
The CVE record carries a CVSS v3.1 base score of 9.3 (Critical), given by its CNA.
FIRST's EPSS model puts the probability of exploitation in the next 30 days at 0.2% (percentile 9.4), as of 29 Oct 2026. EPSS is a statistical estimate, not a report of exploitation.
CISA's SSVC assessment in the CVE record: exploitation poc, automatable no, technical impact total.

Source: CISA Known Exploited Vulnerabilities (KEV) catalog, 2026.10.28, as of 28 Oct 2026; CVE List V5 (CVE Program), cve_2026-10-29_0000Z, as of 29 Oct 2026; FIRST Exploit Prediction Scoring System (EPSS), v2026.06.15, as of 29 Oct 2026. About the data.

Description

TinaCMS admin preview iframe loads an attacker-controlled origin from the URL fragment

Tina is a headless content management system. Prior to tinacms 3.14.0 and @tinacms/app 2.5.14, the /~/* admin preview route in packages/tinacms/src/admin/index.tsx can turn an attacker-controlled hash-router splat into an off-origin iframe URL through packages/@tinacms/app/src/preview.tsx, while packages/@tinacms/app/src/lib/preview-origin.ts derives expectedOrigin from that same URL for the GraphQL message channel in packages/@tinacms/app/src/lib/graphql-reducer.ts. An unauthenticated attacker can send a crafted link to a signed-in editor, cause the admin to frame an attacker origin, and have that frame treated as the trusted preview. The attacker-controlled frame can submit GraphQL reads or mutations that the admin executes with the editor credentials, exposing or modifying protected content. This issue is fixed in tinacms 3.14.0 and @tinacms/app 2.5.14.

Source: CVE List V5 (CVE Program), cve_2026-10-29_0000Z, as of 29 Oct 2026. About the data.

Weakness

CWE-346: Origin Validation Error
CWE-441: Unintended Proxy or Intermediary ('Confused Deputy')
CWE-601: URL Redirection to Untrusted Site ('Open Redirect')

CWE and CAPEC are maintained by MITRE; the entries are those named in the CVE record.

Timeline

Date	Event
9 Oct 2026	CVE record published
13 Oct 2026	CVE record last updated