CVE-2026-48801
linkify-it O(N²) regex scan allows DoS via crafted Markdown
Is CVE-2026-48801 being exploited?
Not confirmed. CVE-2026-48801 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 0.37% probability of exploitation in the next 30 days.
How severe is CVE-2026-48801?
CVE-2026-48801 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-2026-48801?
Yes. A fix has been recorded for CVE-2026-48801. The vendor advisory is the authority on the exact fixed version — apply it from there rather than from a summary.
What does CVE-2026-48801 affect?
CVE-2026-48801 affects linkify-it <5.0.1, Node.js apps rendering untrusted Markdown with linkify:true, Web services that synchronously render Markdown, Static site generators/plugins using linkify-it. Confirm the exact affected versions against the vendor advisory before deciding you are exposed.
What should I do about CVE-2026-48801?
Upgrade to linkify-it v5.0.1+, sanitize/limit Markdown input, and apply rate-limiting
Exploitation status reflects CISA's KEV catalog as we last synced it. Check the catalog directly.
Remote Denial of Service: crafted Markdown with many fuzzy links triggers O(N²) CPU/memory, exhausting worker processes.
Patch when possible
- affected< 5.0.1
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.