CVE-2026-43980 is a medium-severity (CVSS 6.3) Cross-site Scripting (XSS) vulnerability in malla. No vendor fix is recorded yet; mitigation options are listed below.
Malla: Stored XSS via Meshtastic node names in multiple frontend pages
Exploitation Status
Proof-of-concept exploit code exists
- CISA’s SSVC triage found public proof-of-concept exploit code for this CVE, though no confirmed active exploitation.
Exploitation and automatability from CISA’s SSVC triage for CVE-2026-43980.
EPSS Exploitation Probability
Probability of exploitation in the next 30 days, from FIRST.org EPSS.
How urgent is this, really
CVE-2026-43980 by exploitation likelihood (EPSS) against impact (CVSS). Outside the shaded patch-first corner.
Where this sits among everything scored
Of 390,400 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Counts from FIRST.org, log-scaled.
Real-World Exposure
mallaReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects PyPI packages — download data is not available via public APIs for these ecosystems.
Description
Node names (long_name, short_name) received via MQTT are stored in SQLite without sanitization and rendered into the DOM without escaping. Any participant on a public Meshtastic MQTT broker can set a malicious node name that executes JavaScript in the browser of every Malla dashboard visitor.
Affected files:
- src/malla/templates/traceroute_graph.html (line ~832)
- src/malla/templates/map.html (lines ~945, 1078)
- src/malla/templates/packet_detail.html (lines ~1402, 1452)
- src/malla/static/js/relay_node_analysis.js (line ~124)
Steps to reproduce
- Publish a Meshtastic NODEINFO_APP packet to any public MQTT broker with long_name set to a HTML entity i.e
<img src=x onerror=alert(1)> - Wait for malla-capture to store it
- Open the dashboard
Impact
Allows unauthenticated remote attackers to execute arbitrary JavaScript in the browser, such as:
- Phishing overlays
- Force redirect to malicious websites
- Injection of arbitrary third-party scripts (no CSP restrictions)
- Browser resource abuse
- Persistent dashboard denial of service
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐍PyPI | malla | all versions | No fix |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for malla, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Remediation status
No patched version of malla has shipped for CVE-2026-43980 yet. Where your build allows, override or pin the dependency away from the vulnerable range, and apply any maintainer-recommended mitigation.
Mitigate without a patch
Escape or sanitise the affected output on the server side rather than relying on client-side filtering, and add a Content-Security-Policy that blocks inline script execution so injected markup cannot run even if it reaches the page.
Frequently Asked Questions
Is CVE-2026-43980 in your dependencies?
Find it across PyPI, including transitive dependencies.