CVE-2026-90893: MISP UserSettingsController CSRF Protection Bypass on setTheme, setHomePage, and eventIndexColumnToggle Endpoints

Is it exploited?

Not on CISA's list. CISA has not added it to the Known Exploited Vulnerabilities catalog as of 29 Oct 2026. If CISA adds it, this page shows it as known exploited.

How likely is exploitation in the next 30 days?

0.3%

EPSS score, percentile 18.1 of all scored records. A probability estimated by FIRST, not a report of exploitation.

How severe?

5.1 Medium

CVSS v4.0 base score, given by the CNA

What should I do?

The fix removes the three affected actions from the Security component's unlockedActions list (which had disabled all CSRF checks) and instead registers them under a … Full textSolution from the CVE record.

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

Advisories and patches (1)

Which versions are affected?

Affected

• before 2.5.46

Versions by product

Source: CISA KEV 2026.10.29, as of 29 Oct 2026; FIRST EPSS, as of 29 Oct 2026; CVE List, as of 29 Oct 2026. About the data.

What to do

Solution (from the CVE record)

The fix removes the three affected actions from the Security component's unlockedActions list (which had disabled all CSRF checks) and instead registers them under a header-only CSRF token validation mechanism (_csrfTokenHeaderOnly). This requires the X-CSRF-Token header to be present and valid on each request while still permitting the AJAX-style calls that lack traditional form fields. Client-side JavaScript and view templates are updated to include the X-CSRF-Token header (sourced from window.csrfToken) in all AJAX and fetch calls to these endpoints, ensuring legitimate same-origin requests continue to function while cross-origin forged requests are rejected.

Advisories and patches

• Security patch (Patch)

This summary is based on the CVE record as of 29 Oct 2026. Check the vendor's advisory before you act: affected versions and fixes can change.

Affected products and versions

As listed in the CVE record.

Source: CVE List, as of 29 Oct 2026. About the data.

About this vulnerability

MISP contains a Cross-Site Request Forgery (CSRF) vulnerability in the UserSettingsController. The actions setTheme, setHomePage, and eventIndexColumnToggle were explicitly added to the Security component's unlockedActions list, which disabled all CSRF validation (both token and field-hash checks) for those endpoints. Because these endpoints accept POST requests and modify per-user application st…

Summary: CVE record, as of 29 Oct 2026.

• CISA has not added CVE-2026-90893 to its Known Exploited Vulnerabilities (KEV) catalog, as of 29 Oct 2026.
• The CVE record was published on 14 Sep 2026.
• The CVE record carries a CVSS v4.0 base score of 5.1 (Medium), given by its CNA.
• FIRST's EPSS model puts the probability of exploitation in the next 30 days at 0.3% (percentile 18.1), as of 29 Oct 2026. EPSS is a statistical estimate, not a report of exploitation.
• CISA's SSVC assessment in the CVE record: exploitation none, automatable no, technical impact partial.
• The credits in the CVE record name Anthropic (Claude) as finder.

Source: CISA KEV 2026.10.29, as of 29 Oct 2026; CVE List, as of 29 Oct 2026; FIRST EPSS, as of 29 Oct 2026. About the data.

Description

MISP UserSettingsController CSRF Protection Bypass on setTheme, setHomePage, and eventIndexColumnToggle Endpoints

MISP contains a Cross-Site Request Forgery (CSRF) vulnerability in the UserSettingsController. The actions setTheme, setHomePage, and eventIndexColumnToggle were explicitly added to the Security component's unlockedActions list, which disabled all CSRF validation (both token and field-hash checks) for those endpoints. Because these endpoints accept POST requests and modify per-user application state (theme selection, default homepage URL, and event index column visibility), an attacker who can induce a logged-in MISP user to load a malicious page (e.g., via a crafted link, embedded image, or auto-submitting form) can forge requests that alter the victim's settings without their knowledge or consent. The most impactful action is setHomePage, which allows an attacker to redirect the victim's default landing page to an arbitrary attacker-controlled URL, potentially facilitating phishing or further social engineering. The setTheme action can alter the user's visual theme, and eventIndexColumnToggle can change which columns are displayed in the event index view. No authentication bypass is involved; the victim must already be authenticated to MISP. The vulnerability was reported by the Scottish Government National Cyber Team. Version affected: ≤2.5.45

Source: CVE List, as of 29 Oct 2026. About the data.

Timeline