CVE-2026-90957

MISP: Stored XSS via Inline-Served SVG Organisation Logos and Report Pictures

Published Sep 14, 2026 CVSS 4.0 · 5.1 Medium EPSS < 1% KEV · Not listed
Description
Affected versions of MISP serve uploaded SVG images inline without a restrictive browser sandbox.


The commit explains that SVG files are XML documents rather than passive bitmap images. While scripts inside SVG do not execute when the SVG is rendered through a normal <img>, they can execute when the SVG is navigated to directly or embedded as a document. In that case, malicious <script> elements, event handlers, or javascript: URLs execute on the MISP origin with the viewer’s session.


The affected use cases include:



 - organisation SVG logos;
 - event-report SVG pictures.






Importantly, the vulnerable behavior is on the serve path, not merely the upload path: the patch notes that a malicious SVG uploaded while SVG support was enabled could remain dangerous even after uploads were later disabled.



Version affected: ≤2.5.45

Remediation

Vendor Solution

A new sandboxInlineFile() method is added to RestResponseComponent. When a file is served inline (download=false) and its type is SVG (svg, svgz, or image/svg+xml), the response is augmented with a Content-Security-Policy header containing the sandbox directive (which assigns an opaque origin and disables script execution, plugins, and form submission) along with restrictive default-src, style-src, img-src, and font-src directives that still permit rendering of inline styles, embedded raster images, and data: fonts. An X-Content-Type-Options: nosniff header is also set. The method is invoked from both the generic sendFile() path and the org-logo endpoint. The enable_svg_logos setting description is updated to warn administrators that SVG files remain XML documents and should be left disabled unless required.

Tracking

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Advisories

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History
Type Values Removed Values Added
First Time appeared Misp
Misp misp
Vendors & Products Misp
Misp misp
Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

Type Values Removed Values Added
Description Affected versions of MISP serve uploaded SVG images inline without a restrictive browser sandbox. The commit explains that SVG files are XML documents rather than passive bitmap images. While scripts inside SVG do not execute when the SVG is rendered through a normal <img>, they can execute when the SVG is navigated to directly or embedded as a document. In that case, malicious <script> elements, event handlers, or javascript: URLs execute on the MISP origin with the viewer’s session. The affected use cases include:  - organisation SVG logos;  - event-report SVG pictures. Importantly, the vulnerable behavior is on the serve path, not merely the upload path: the patch notes that a malicious SVG uploaded while SVG support was enabled could remain dangerous even after uploads were later disabled. Version affected: ≤2.5.45
Title MISP: Stored XSS via Inline-Served SVG Organisation Logos and Report Pictures
Weaknesses CWE-693
CWE-79
References
Metrics cvssV4_0

{'score': 5.1, 'vector': 'CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:P/VC:L/VI:L/VA:N/SC:L/SI:L/SA:N'}

Weaknesses

Sources

Status
PUBLISHED
Assigner
CIRCL
Published
Updated
Sep 14, 2026, 1:58 PM
Reserved
Sep 14, 2026, 1:02 PM
Status
Deferred
Published
Sep 14, 2026, 1:19 PM
Modified
Sep 16, 2026, 1:42 PM