CVE•Published 2026-09-07•Modified 2026-09-09•0 articles on news•4 live references•NVD data

CVE-2026-86428Thephpleague · Commonmark

Vulnerability data via NVD (ingested)

CVSS v3.1

7.5

HIGH

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

EPSS percentile

Exploit Prediction Scoring System · top 80% of all CVEs

Weaknesses (CWE)

CWE-407Inefficient Algorithmic Complexity

Description

commonmark versions from 1.5.0 before 2.10.0 contain a denial of service vulnerability in the AttributesExtension when processing distinctly-named attributes. Attackers can submit Markdown with numerous distinct attribute names to cause quadratic-time attribute merging and filtering, consuming disproportionate CPU resources and preventing legitimate requests from completing.

Timeline

Published 2026-09-07

Modified 2026-09-09

External references

NVD MITRE Exploit-DB VulnCheck

Search for exposed instances

Shodan + Censys queries derived from NVD's CPE data. The vuln tag catches assets Shodan has explicitly linked to this CVE; the product / banner fingerprints find exposed instances even when the vuln tag was never applied (which is common). Live host counts are a Premium feature.

Shodan · vuln tag

vuln:CVE-2026-86428

Hosts Shodan has explicitly fingerprinted as vulnerable.

Shodan · product

product:"Thephpleague Commonmark"

All exposed Thephpleague Commonmark instances — cross-reference with the CVE's affected-version range.

Shodan · banner/body mention

http.html:"Commonmark"

HTTP body or banner mentions "Commonmark" — catches deploys Shodan didn't identify as a product.

More intel sources (5)

Shodan report

vuln:CVE-2026-86428