High 7.5Published Jul 8, 2026

CVE-2026-59887linkify-it: Quadratic-complexity DoS via the `mailto:` validator scan-loop on attacker text

Updated under an hour ago (Oct 28, 2026, 5:00 AM ET)

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It affects markdown-it linkify-it and 1 other product. Add what you run to find out whether that includes you.

No exploitation reported and no EPSS estimate yet.

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Every CVE for markdown-it linkify-it

Exploited in the last 30 days

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.

CVSS: 7.5 HIGH (v3.1, CNA)CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Weakness (CWE): CWE-407
Known exploited: Not in CISA's KEV catalog
EPSS (exploitation in the next 30 days): Not loaded for this CVE
Assigned by: GitHub_M
NVD analysis: Analyzed
Record last updated: Jul 9, 2026
First seen by InfoSec Signals: Oct 9, 2026

Affected products

Affected products

markdown-it linkify-it markdown_it:linkify_it (from the name)	before 5.0.2	CNA record
markdown-it linkify-it markdown-it:linkify-it	before 5.0.2	NVD

References

References

https://github.com/markdown-it/linkify-it/security/advisories/GHSA-v245-v573-v5vm	x-refsource-confirm, exploit, mitigation, vendor-advisory
https://github.com/markdown-it/linkify-it/commit/105e5d77f7d119871d2b2d86ed208568eb3e7ffe	x-refsource-misc, patch
https://github.com/markdown-it/linkify-it/releases/tag/5.0.2	x-refsource-misc, release-notes

The CVE record on cve.org NVD's entry

The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.