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

Goal: 1000 CNY · Raised: 1359 CNY

100%
Buy Us a Coffee

CVE-2026-115349— Mistune 3.0.0 before 3.3.0 Denial of Service via Nested Bracket Parsing

Quick assessment

Affected
lepture mistune
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.

Mistune 3.0.0 至 3.3.0 之前的版本在 中的 函数存在算法复杂度拒绝服务漏洞。攻击者可提交包含深度嵌套方括号的 Markdown 内容，从而触发二次方解析时间，仅需构造极小的恶意请求即可耗尽服务器 CPU 资源。

CVSS 7.5 · High

Possible ATT&CK Techniques 1 AI

T1499.003 · Application Exhaustion Flood

Affected Version Matrix 2

VendorProduct Version RangeStatus
lepture mistune 3.0.0< 3.3.0 affected
3.3.0 unaffected
Get alerts for future matching vulnerabilities Log in to subscribe

I. Basic Information for CVE-2026-115349

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Although we use advanced large model technology, its output may still contain inaccurate or outdated information.Shenlong tries to ensure data accuracy, but please verify and judge based on the actual situation.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
Mistune 3.0.0 before 3.3.0 Denial of Service via Nested Bracket Parsing
Source: CVE Program / CVE List V5
Vulnerability Description
Mistune from 3.0.0 before 3.3.0 contains an algorithmic complexity denial of service vulnerability in the parse_link_text function in src/mistune/helpers.py. Attackers can submit markdown with deeply nested square brackets triggering quadratic parsing time, exhausting server CPU with small crafted requests.
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
CWE-1333
Source: CVE Program / CVE List V5

Affected Products

Vendor Product Affected Versions CPE Subscribe
lepture mistune 3.0.0 ~ 3.3.0 -

II. Public POCs for CVE-2026-115349

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

No public POC found.

Login to generate AI POC

III. Intelligence Information for CVE-2026-115349

请登录查看更多情报信息。

Vendor Advisories for CVE-2026-115349 (2)

Same Patch Batch · lepture · 2026-10-22 · 9 CVEs total

CVE-2026-115353 8.6 HIGH Mistune before 3.3.0 Path Traversal via include Directive
CVE-2026-115352 7.5 HIGH Mistune before 3.3.0 Quadratic-Time DoS via Unmatched Brackets in Inline Parser
CVE-2026-115348 7.5 HIGH Mistune before 3.3.0 Quadratic-Time DoS via parse_link_text
CVE-2026-115347 7.5 HIGH Mistune before 3.3.0 Quadratic Denial of Service via parse_link_text
CVE-2026-115355 7.5 HIGH Mistune before 3.3.0 Path Traversal and XSS via Include Directive
CVE-2026-115354 6.5 MEDIUM Mistune before 3.3.0 Arbitrary Local File Read via Include Directive
CVE-2026-115350 6.1 MEDIUM Mistune before 3.3.0 Stored XSS via Include Directive HTML Files
CVE-2026-115351 4.7 MEDIUM Mistune 3.2.1 before 3.3.0 CSS Injection via Figure Directive figwidth Option

IV. Related Vulnerabilities

Same product: mistune
Same vendor: lepture
Same weakness: CWE-1333

V. Comments for CVE-2026-115349

No comments yet

Leave a comment