lepture mistune up to 3.2.x Safe URL Filter html.py safe_url cross site scripting

CVSS Meta Temp Score
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CTI Interest Score
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4.1$0-$5k0.58+

Summaryinfo

A vulnerability was found in lepture mistune up to 3.2.x. It has been declared as problematic. This affects the function safe_url of the file src/mistune/renderers/html.py of the component Safe URL Filter. Such manipulation leads to cross site scripting. This vulnerability is listed as CVE-2026-59929. The attack may be performed from remote. There is no available exploit.

Detailsinfo

A vulnerability was found in lepture mistune up to 3.2.x. It has been rated as problematic. Affected by this issue is the function safe_url of the file src/mistune/renderers/html.py of the component Safe URL Filter. The manipulation with an unknown input leads to a cross site scripting vulnerability. Using CWE to declare the problem leads to CWE-79. The product does not neutralize or incorrectly neutralizes user-controllable input before it is placed in output that is used as a web page that is served to other users. Impacted is integrity. CVE summarizes:

Mistune is a Python Markdown parser with renderers and plugins. Prior to 3.3.0, the safe_url filter in src/mistune/renderers/html.py blocks only javascript:, vbscript:, file:, and data: schemes, allowing legacy or chained schemes such as feed:, view-source:, jar:, livescript:, mocha:, ms-its:, mk:, and res: to reach rendered href and src attributes and potentially execute script in affected user agents. This issue is fixed in version 3.3.0.

The advisory is shared for download at github.com. This vulnerability is handled as CVE-2026-59929 since 07/07/2026. The exploitation is known to be easy. The attack may be launched remotely. No form of authentication is required for exploitation. Successful exploitation requires user interaction by the victim. There are known technical details, but no exploit is available. The MITRE ATT&CK project declares the attack technique as T1059.007.

Upgrading to version 3.3.0 eliminates this vulnerability.

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Productinfo

Vendor

Name

Version

Website

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 4.3
VulDB Meta Temp Score: 4.1

VulDB Base Score: 4.3
VulDB Temp Score: 4.1
VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv2info

AVACAuCIA
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VectorComplexityAuthenticationConfidentialityIntegrityAvailability
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VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Cross site scripting
CWE: CWE-79 / CWE-94 / CWE-74
CAPEC: 🔒
ATT&CK: 🔒

Physical: No
Local: No
Remote: Yes

Availability: 🔒
Status: Not defined
Price Prediction: 🔍
Current Price Estimation: 🔒

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Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: no mitigation known
Status: 🔍

0-Day Time: 🔒

Upgrade: mistune 3.3.0

Timelineinfo

07/07/2026 CVE reserved
07/08/2026 +1 days Advisory disclosed
07/08/2026 +0 days VulDB entry created
07/08/2026 +0 days VulDB entry last update

Sourcesinfo

Product: github.com

Advisory: github.com
Status: Confirmed

CVE: CVE-2026-59929 (🔒)
GCVE (CVE): GCVE-0-2026-59929
GCVE (VulDB): GCVE-100-376928

Entryinfo

Created: 07/08/2026 18:53
Changes: 07/08/2026 18:53 (55)
Complete: 🔍
Cache ID: 216::103

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