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CVE-2026-115351— Mistune 3.2.1 before 3.3.0 CSS Injection via Figure Directive figwidth Option

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 3.2.1 至 3.3.0 之前的版本存在 CSS 注入漏洞。该漏洞允许能够控制 Markdown 输入的攻击者，通过未经验证的 指令中的 选项注入任意样式声明。攻击者可以向渲染后的 元素的 属性追加如 之类的声明，从而迫使受害者的浏览器向攻击者服务器发送请求，并泄露属性值。

CVSS 4.7 · Medium

Possible ATT&CK Techniques 1 AI

T1190 · Exploit Public-Facing Application

Affected Version Matrix 2

VendorProduct Version RangeStatus
lepture mistune 3.2.1< 3.3.0 affected
3.3.0 unaffected
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I. Basic Information for CVE-2026-115351

Vulnerability Information
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Vulnerability Title
Mistune 3.2.1 before 3.3.0 CSS Injection via Figure Directive figwidth Option
Source: CVE Program / CVE List V5
Vulnerability Description
Mistune from 3.2.1 before 3.3.0 contains a CSS injection vulnerability that allows attackers controlling markdown input to inject arbitrary style declarations via the unvalidated figwidth option of the figure directive. Attackers can append declarations like background:url() to the rendered figure style attribute, forcing victim browsers to send requests to attacker servers and leak attribute values.
Source: CVE Program / CVE List V5
CVSS Information
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:N/A:N
Source: CVE Program / CVE List V5
Vulnerability Type
对生成代码的控制不恰当(代码注入)
Source: CVE Program / CVE List V5

Affected Products

Vendor Product Affected Versions CPE Subscribe
lepture mistune 3.2.1 ~ 3.3.0 -

II. Public POCs for CVE-2026-115351

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III. Intelligence Information for CVE-2026-115351

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Vendor Advisories for CVE-2026-115351 (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-2026-115349 7.5 HIGH Mistune 3.0.0 before 3.3.0 Denial of Service via Nested Bracket Parsing
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

IV. Related Vulnerabilities

Same product: mistune
Same vendor: lepture
Same weakness: CWE-94

V. Comments for CVE-2026-115351

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