CVE-2026-59887: linkify-it is a links recognition library with full Unicode support

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HIGH 7.5REMOTEUPGRADE

CVE-2026-59887 is a high-severity flaw (CVSS 7.5) affecting linkify-it. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

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.

Why this priority

High severity
Public exploit reference
Remotely exploitable, no login, no user action

A fixed release or distro patch exists.

Risk facts

CVSS score	7.5 (High)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	0.6% (top 49%)
CISA exploited list	No
Weakness	CWE-407
Published	2026-07-08
Last modified	2026-10-25

Publisher (CNA): GitHub, Inc. · Vendor: markdown-it

Last updated 2026-10-25 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2026-07-08 17:17 UTCPublished CVE record published
2026-10-25 17:10 UTCUpdated Record last modified

markdown-it linkify-it UPGRADE

Affected: < 5.0.2

Fixed in: 5.0.2

Safe to downgrade to: no unaffected older release

1. Check installed version

npm ls linkify-it

2. UPGRADE to 5.0.2

npm install linkify-it@">=5.0.2"

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2026-59887?

linkify-it: upgrade to 5.0.2. Exact commands for each OS are on this page.

Is CVE-2026-59887 being exploited?

CVE-2026-59887 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2026-59887 affect?

CVE-2026-59887 affects linkify-it. Severity is high (CVSS 7.5). 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

How urgent is CVE-2026-59887?

Priority 49/100. High severity; Public exploit reference; Remotely exploitable, no login, no user action

Related CVEs

CVE-2026-48801 HIGH 7.5 UPGRADE linkify-it is a links recognition library with full Unicode support

References

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