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CVE-2026-54393 misp CVE debrief

A stored cross-site scripting vulnerability exists in MISP when the Overmind theme is used. The setHomePage endpoint previously saved the user-controlled path value through setSettingInternal(), bypassing the normal setSetting() validation logic, including validate_homepage, which requires homepage paths to start with /. As a result, an authenticated user could store an arbitrary homepage value, including an XSS payload. The stored value was later rendered in app/View/News/index.ctp as the href attribute of the “Continue to homepage” link without HTML escaping. This could allow execution of attacker-controlled JavaScript in the browser context of the affected MISP instance when the crafted homepage link is rendered and interacted with. The issue is fixed by always persisting the homepage setting through setSetting(), ensuring validation and access checks are applied, and by HTML-escaping the homepage value before rendering it in the news view.

Vendor
misp
Product
Unknown
CVSS
MEDIUM 5.1
CISA KEV
Not listed in stored evidence
Original CVE published
2026-06-12
Original CVE updated
2026-06-15
Advisory published
2026-06-12
Advisory updated
2026-06-15

Who should care

Users of MISP with the Overmind theme installed should be aware of this vulnerability and take steps to mitigate it.

Technical summary

The vulnerability exists due to improper validation and sanitization of user-controlled input in the setHomePage endpoint. An authenticated user can exploit this vulnerability to store an arbitrary homepage value, including an XSS payload, which can be executed in the browser context of the affected MISP instance.

Defensive priority

MEDIUM

Recommended defensive actions

  • Update MISP to the latest version that includes the fix for this vulnerability.
  • Ensure that the Overmind theme is updated to the latest version.
  • Restrict access to the setHomePage endpoint to only authorized users.
  • Implement additional security measures, such as input validation and output encoding, to prevent similar vulnerabilities.

Evidence notes

The CVE record for CVE-2026-54393 provides additional information about this vulnerability.

Sources and references

Verified primary and authoritative sources

  • CVE-2026-54393 CVE Program record

    Publisher, destination, and source semantics verified

    URL: https://www.cve.org/CVERecord?id=CVE-2026-54393

    CVE Program - Official CVE Program record with source-provided CVE metadata.

  • CVE-2026-54393 NVD vulnerability detail

    Publisher, destination, and source semantics verified

    URL: https://nvd.nist.gov/vuln/detail/CVE-2026-54393

    NIST National Vulnerability Database - Official NIST NVD detail page and source-specific vulnerability assessment.

Supplemental references

  • Source reference

    Unverified legacy reference

    URL: https://github.com/MISP/MISP/commit/d4733ca5d2fcceb12abc72ec6069f2484e3b8ec2

    5a6e4751-2f3f-4070-9419-94fb35b644e8

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.