CVE-2026-58500
Stored XSS in MCP Appium UI allows JS injection to invoke MCP tools.
Is CVE-2026-58500 being exploited?
Not confirmed. CVE-2026-58500 does not appear in CISA's Known Exploited Vulnerabilities catalog, which records only exploitation that has been observed and reported publicly. That is evidence of absence of a report, not evidence the flaw is unattacked. EPSS currently estimates a 0.35% probability of exploitation in the next 30 days.
How severe is CVE-2026-58500?
CVE-2026-58500 is rated High with a CVSS score of 8.2. Severity describes how bad exploitation would be, not how likely it is: pair it with exploitation evidence before deciding what to patch first.
Is there a patch for CVE-2026-58500?
Yes. A fix has been recorded for CVE-2026-58500. The vendor advisory is the authority on the exact fixed version — apply it from there rather than from a summary.
What does CVE-2026-58500 affect?
CVE-2026-58500 affects MCP Appium < 1.85.10, MCP client web UI, Mobile apps under test (attack vector). Confirm the exact affected versions against the vendor advisory before deciding you are exposed.
What should I do about CVE-2026-58500?
Upgrade to MCP Appium 1.85.10+, sanitize/escape UI inputs, restrict untrusted UIs.
Exploitation status reflects CISA's KEV catalog as we last synced it. Check the catalog directly.
Attacker-controlled app UI can inject JavaScript into MCP client, invoking tools via postMessage to take screenshots, read page source, or perform other registered actions.
Patch when possible
- affected< 1.85.10
As published in the CVE Program record. A version outside these ranges is not a statement that it is unaffected — vendors sometimes understate a range, and distribution-backported builds carry upstream numbers that do not reflect what was patched into them.