Reference page — cumulative record through Sunday, October 4, 2026 UTC. Reference pages update as the archive grows; only dated daily editions are immutable pages of record.
CVE-2026-59887
markdown-it linkify-it — linkify-it: Quadratic-complexity DoS via the `mailto:` validator scan-loop on attacker text
AV AC PR UI S C I A CVSS EPSS %ile KEV
N L N N U N N H 7.5 .0064 49.1 —
AFFECTED
Product Versions Fixed
linkify-it < 5.0.2 – —
TIMELINE
Jul 7 Reserved by GitHub_M
Jul 8 Published (CNA: GitHub_M)
Aug 26 EXPLOIT PUBLISHED — CVE-2026-59887 (markdown-it linkify-it). Public exploit reference added.
Description
linkify-it is a links recognition library with full Unicode support. Prior to 5.0.2, the mailto: schema validator used by .test() and .match() can be invoked at every mailto: occurrence and scan the remaining input through src_email_name in lib/re.mjs, causing O(n^2) CPU consumption on crafted user text. This issue is fixed in version 5.0.2.
Lifecycle
Complete event history — 3 events, chronological
| Date | Event | Detail |
|---|
| July 7, 2026 | Reserved | Reserved by GitHub_M |
| July 8, 2026 | Published | Published (CNA: GitHub_M) |
| August 26, 2026 | EXPLOIT PUBLISHED | EXPLOIT PUBLISHED — CVE-2026-59887 (markdown-it linkify-it). Public exploit reference added. |
Affected
Affected products and packages — 1 row
| Vendor | Product / Package | Ecosystem | Version introduced | Fixed |
|---|
| markdown-it | linkify-it | — | < 5.0.2 | — |
About this page
This is a reference page, not a dated page of record. It assembles the complete lifecycle of CVE-2026-59887 from the CVE Program record, NVD enrichment, the CISA KEV catalog, EPSS, and OSV advisories. The box score's numbers (CVSS, EPSS, KEV status) are current as of Sunday, October 4, 2026 UTC and are re-derived as the archive grows; only dated daily editions are immutable pages of record. The authoritative source for this identifier is cve.org.
