Goal Reached Thanks to every supporter — we hit 100%!

Goal: 1000 CNY · Raised: 1359 CNY

100%
Buy Us a Coffee

CVE-2026-86435— commonmark 1.5.0 before 2.8.4 Denial of Service via Footnote

Quick assessment

Affected
thephpleague commonmark
Exploitation
No confirmed in-the-wild exploitation; assess based on exposure
Recommended action
Check the vendor advisory and references for a fixed version. If immediate upgrade is impossible, restrict exposure and increase monitoring.

The League of Extraordinary Packages league/commonmark是The League of Extraordinary Packages组织开源的一款Markdown解析组件。 The League of Extraordinary Packages league/commonmark 1.5.0版本至2.8.4之前版本存在资源管理错误漏洞，该漏洞源于脚注扩展未对脚注定义进行去重，可能导致攻击者构造包含重复脚注定义和引用的文档，造成二次方输出扩张，消耗过多内存

CVSS 7.5 · High EPSS 0.49% · P41

Affected Version Matrix 2

VendorProduct Version RangeStatus
thephpleague commonmark 1.5.0< 2.8.4 affected
2.8.4 unaffected
Get alerts for future matching vulnerabilities Log in to subscribe

I. Basic Information for CVE-2026-86435

Vulnerability Information
Have questions about the vulnerability? See if Shenlong's analysis helps!
View Shenlong Deep Dive ↗

Although we use advanced large model technology, its output may still contain inaccurate or outdated information.Shenlong tries to ensure data accuracy, but please verify and judge based on the actual situation.

Vulnerability Title
commonmark 1.5.0 before 2.8.4 Denial of Service via Footnote
Source: CVE Program / CVE List V5
Vulnerability Description
commonmark versions from 1.5.0 before 2.8.4 contain a denial of service vulnerability in the Footnote extension that fails to deduplicate footnote definitions. Attackers can craft documents with duplicate footnote definitions and references to create quadratic output expansion, consuming excessive memory and CPU to exhaust server resources.
Source: CVE Program / CVE List V5
CVSS Information
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Source: CVE Program / CVE List V5
Vulnerability Type
算法复杂性
Source: CVE Program / CVE List V5
Vulnerability Title
The League of Extraordinary Packages league/commonmark 资源管理错误漏洞
Source: CNNVD (China National Vulnerability Database)
Vulnerability Description
The League of Extraordinary Packages league/commonmark是The League of Extraordinary Packages组织开源的一款Markdown解析组件。 The League of Extraordinary Packages league/commonmark 1.5.0版本至2.8.4之前版本存在资源管理错误漏洞，该漏洞源于脚注扩展未对脚注定义进行去重，可能导致攻击者构造包含重复脚注定义和引用的文档，造成二次方输出扩张，消耗过多内存
Source: CNNVD (China National Vulnerability Database)
CVSS Information
N/A
Source: CNNVD (China National Vulnerability Database)
Vulnerability Type
N/A
Source: CNNVD (China National Vulnerability Database)

Affected Products

Vendor Product Affected Versions CPE Subscribe
thephpleague commonmark 1.5.0 ~ 2.8.4 -

II. Public POCs for CVE-2026-86435

# POC Description Source Link Shenlong Link
AI-Generated POC Premium

No public POC found.

Login to generate AI POC

III. Intelligence Information for CVE-2026-86435

请登录查看更多情报信息。

Vendor Advisories for CVE-2026-86435 (2)

Same Patch Batch · thephpleague · 2026-09-07 · 8 CVEs total

CVE-2026-86430 7.5 HIGH league/commonmark before 2.9.1 Denial of Service via parsing
CVE-2026-86429 7.5 HIGH commonmark before 2.9.1 Denial of Service via SmartPunct and Attributes
CVE-2026-86434 7.5 HIGH commonmark 2.0.0 through 2.8.3 Denial of Service via Slug Collision
CVE-2026-86433 7.5 HIGH commonmark 1.5.0 before 2.8.4 Denial of Service via Attributes
CVE-2026-86428 7.5 HIGH commonmark 1.5.0 before 2.10.0 Denial of Service via Attributes
CVE-2026-86431 7.2 HIGH commonmark before 2.9.1 XSS via AttributesExtension form feed bypass
CVE-2026-86432 5.3 MEDIUM commonmark 2.0.0 before 2.8.4 Denial of Service via XML

IV. Related Vulnerabilities

Same product: commonmark
Same vendor: thephpleague
Same weakness: CWE-407