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Fencer Intel
medium 5.1

CVE-2026-90957 json

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

published last mo. modified last mo. also EUVD-2026-77467

cvss
5.1
version 4.0, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.4%
EPSS 0.4% chance of exploitation in 30 days, percentile 34%
public exploits
0
none known

Summary

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

Patch / fix

  • MISP MISP 2.5.46

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CISA SSVC

Exploitation
none
Automatable
no
Technical impact
partial
Assessed
last mo.

Exploit prediction

0.40% chance of exploitation in the next 30 days, higher than 34% of all scored CVEs (FIRST EPSS, 2026-11-11).

CVSS scores

assigned by version score vector
CNA 4.0 5.1 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
CNA 4.0 5.1 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/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

Affected products

  • MISP MISP

Classification

Weakness
  • CWE-79 Improper Neutralization of Input During Web Page Generation
  • CWE-693 Protection Mechanism Failure

References

Sources

Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.