CVE-2026-115351

Mistune 3.2.1 before 3.3.0 CSS Injection via Figure Directive figwidth Option

MEDIUM
4.7
CVSS Score
Published: October 22, 2026 at 07:13 PM UTC
Updated: October 29, 2026 at 12:17 PM UTC
1 product affected across 1 vendorProject Mistune

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Severity
MEDIUM4.7
Exploit prediction
EPSS 0.2%
SSVC
PoC

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.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

Vendor states this is fixed in 3.3.0 (unaffected)

Remediation

No guide yet

No remediation guidance has been written for this CVE yet. What the record does show:

SSVC — Action Prioritization

SSVCPoCNot automatablePartial impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

4.7MEDIUMVulnCheck
Attack Vector
NETWORK
Complexity
LOW
Privileges
NONE
User Interaction
REQUIRED
Scope
CHANGED
Confidentiality
LOW
Integrity
NONE
Availability
NONE
Vector?

Quick Info

StatusDEFERRED
CWE
CWE-94

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