CVE-2026-40262
Authenticated HTML/SVG upload enables XSS in Mark app.
Is CVE-2026-40262 being exploited?
Not confirmed. CVE-2026-40262 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 0.31% probability of exploitation in the next 30 days.
How severe is CVE-2026-40262?
CVE-2026-40262 is rated High with a CVSS score of 8.7. 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-2026-40262?
Yes. A fix has been recorded for CVE-2026-40262. The vendor advisory is the authority on the exact fixed version — apply it from there rather than from a summary.
What does CVE-2026-40262 affect?
CVE-2026-40262 affects Mark open-source note-taking app, 0.19.1 and earlier. Confirm the exact affected versions against the vendor advisory before deciding you are exposed.
What should I do about CVE-2026-40262?
Upgrade to 0.19.2+; restrict HTML/SVG uploads; enable nosniff.
Exploitation status reflects CISA's KEV catalog as we last synced it. Check the catalog directly.
Executes JS in the victim's browser under app origin, enabling API actions and data access using the victim's session.
Patch when possible
- affected< 0.19.2
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.