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CVE-2026-53693 misp CVE debrief

A stored cross-site scripting vulnerability existed in MISP BSimVis tag rendering code. Several client-side rendering paths interpolated tag names, collection names, entity identifiers, cluster names, and tag metadata directly into HTML, HTML attributes, inline JavaScript event handlers, and CSS style values without context-appropriate escaping. The patch adds shared escaping helpers for HTML, attributes, JavaScript strings, and CSS color validation, then applies them across tag badges, tooltips, context menus, cluster cards, autocomplete suggestions, and dynamically inserted tag cards. An attacker able to create or influence stored tag or metadata values could inject a crafted payload that is later rendered in another user’s browser. Successful exploitation could execute arbitrary JavaScript in the victim’s session when they view affected BSimVis pages, potentially allowing the attacker to perform actions as the victim, read data available to the victim, or alter displayed application content. This issue affects MISP bsimvis: through v0.2.0.

Vendor
misp
Product
bsimvis
CVSS
MEDIUM 6.9
CISA KEV
Not listed in stored evidence
Original CVE published
2026-06-10
Original CVE updated
2026-06-10
Advisory published
2026-06-10
Advisory updated
2026-06-10

Who should care

Users of MISP BSimVis, particularly those who can create or influence stored tag or metadata values.

Technical summary

The vulnerability allows an attacker to inject a crafted payload that is later rendered in another user’s browser, potentially allowing the attacker to perform actions as the victim, read data available to the victim, or alter displayed application content.

Defensive priority

MEDIUM

Recommended defensive actions

  • Apply the patch that adds shared escaping helpers for HTML, attributes, JavaScript strings, and CSS color validation.
  • Ensure that users with the ability to create or influence stored tag or metadata values are aware of the vulnerability and take necessary precautions.

Evidence notes

The vulnerability has a CVSS score of 6.9 and is classified as MEDIUM severity.

Sources and references

Verified primary and authoritative sources

  • CVE-2026-53693 CVE Program record

    Publisher, destination, and source semantics verified

    URL: https://www.cve.org/CVERecord?id=CVE-2026-53693

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

  • CVE-2026-53693 NVD vulnerability detail

    Publisher, destination, and source semantics verified

    URL: https://nvd.nist.gov/vuln/detail/CVE-2026-53693

    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/bsimvis/commit/7bcd2c2e27647dccdfb71877e905fbb032124a63

    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.