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Cross-site Scripting (XSS)Weakness · CWE-79

CVE-2026-54393

MEDIUM · 5.1 CVSS v4.0 Published 2026-06-12
Patch available
A vendor patch is available. No clean upgrade release — apply the published patch.
See remediation →
58/100
Remediation priority · Elevated
Remotely reachable No privileges Patch available

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
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.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis
How this class of weakness works · CWE-79

Untrusted input is placed into a web page without being neutralised, so an attacker's markup or script executes in another user's browser. That can hijack sessions, capture keystrokes, or silently perform actions as the victim. Fixing it properly means context-aware output encoding everywhere data meets HTML, backed by a content-security policy as a second line of defence.

General guidance for the cross-site scripting (xss) class — the official description and references above are authoritative for this specific CVE. Want a bespoke review and a reviewed fix? Ask our team →

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Network
Complexity
Low
Privileges
None
Authentication
X
User interaction
A
Scope
X

CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Patch available Apply the vendor patch
Vendor patch github.com →
Recommended fix Moderate confidence

MISP version containing commit d4733ca5d2fcceb12abc72ec6069f2484e3b8ec2 (check MISP releases after the commit date)

  1. Identify your current MISP version by checking the git tag (e.g., git tag -l) or the version file in your installation
  2. Locate the affected file app/View/News/index.ctp and apply HTML escaping to the homepage value before rendering it in the href attribute (use h() function or htmlspecialchars())
  3. Locate the setHomePage function in your MISP installation (likely in app/Controller/UsersController.php or similar)
  4. Modify the setHomePage endpoint to use setSetting() instead of setSettingInternal() to ensure validation and access checks are applied
  5. Alternatively, cherry-pick the specific commit: git cherry-pick d4733ca5d2fcceb12abc72ec6069f2484e3b8ec2
  6. After applying the patch, clear any caches (e.g., rm -rf app/tmp/cache/*)
  7. Verify the fix by attempting to set a homepage with JavaScript payload - it should either be rejected by validation or properly escaped when rendered

Generated from the published advisory — verify against the referenced sources before acting.

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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

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Peer-ranked notes from engineers who’ve handled CVE-2026-54393 in production — separate from our analysis above.

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