How severe is CVE-2026-59887?

CVE-2026-59887 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.

Is CVE-2026-59887 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (50th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2026-59887?

CVE-2026-59887 affects Markdown-it Linkify-it. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2026-59887?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.

When was CVE-2026-59887 published?

CVE-2026-59887 was published on 2026-07-08 and last updated on 2026-08-26.

CVE-2026-59887

CVE-2026-59887 is a high-severity vulnerability in Markdown-it Linkify-it with a CVSS 3.x base score of 7.5. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-407.

Key facts

Severity: High (CVSS 3.x base score 7.5)
EPSS exploit prediction: 1% (50th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-407
Affected product: Markdown-it Linkify-it
Published: 2026-07-08
Last modified: 2026-08-26

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.

Frequently asked questions

What is CVE-2026-59887?: 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.
How severe is CVE-2026-59887?: CVE-2026-59887 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.
Is CVE-2026-59887 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (50th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-59887?: CVE-2026-59887 affects Markdown-it Linkify-it. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2026-59887?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
When was CVE-2026-59887 published?: CVE-2026-59887 was published on 2026-07-08 and last updated on 2026-08-26.

References

Affected products (1)

cpe:2.3:a:markdown-it:linkify-it:*:*:*:*:*:node.js:*:*

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