pfefferle Webmention Plugin up to 5.8.0 on WordPress Webmention REST Endpoint esc_attr cross site scripting

CVSS Meta Temp Score
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CTI Interest Score
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5.6$0-$5k1.32-

Summaryinfo

A vulnerability classified as problematic has been found in pfefferle Webmention Plugin up to 5.8.0 on WordPress. This vulnerability affects the function esc_attr of the component Webmention REST Endpoint. This manipulation causes cross site scripting. This vulnerability is registered as CVE-2026-10513. Remote exploitation of the attack is possible. No exploit is available. It is recommended to upgrade the affected component.

Detailsinfo

A vulnerability classified as problematic was found in pfefferle Webmention Plugin up to 5.8.0 on WordPress. Affected by this vulnerability is the function esc_attr of the component Webmention REST Endpoint. The manipulation with an unknown input leads to a cross site scripting vulnerability. The CWE definition for the vulnerability is 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. As an impact it is known to affect integrity. The summary by CVE is:

The Webmention plugin for WordPress is vulnerable to Stored Cross-Site Scripting in versions up to and including 5.8.0 via parser-derived 'avatar' and 'url' author metadata. This is due to insufficient input sanitization and output escaping on user-supplied MF2 author properties processed by the unauthenticated webmention REST endpoint and rendered directly into HTML 'value' attributes by the edit-comment-form template without esc_attr() or esc_url(). This makes it possible for unauthenticated attackers to inject arbitrary web scripts in pages that will execute whenever a privileged user (moderator or administrator) opens the affected comment edit screen.

The weakness was published by Volodymyr Kolesnykov. The advisory is shared at wordfence.com. This vulnerability is known as CVE-2026-10513 since 06/01/2026. The exploitation appears to be easy. The attack can be launched remotely. The exploitation doesn't need any form of authentication. It demands that the victim is doing some kind of user interaction. Technical details are known, but no exploit is available. MITRE ATT&CK project uses the attack technique T1059.007 for this issue.

Upgrading to version 5.7.0 eliminates this vulnerability.

Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

Productinfo

Type

Vendor

Name

Version

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 5.7
VulDB Meta Temp Score: 5.6

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

CNA Base Score: 7.2
CNA Vector (Wordfence): 🔒

CVSSv2info

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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

EPSS Score: 🔒
EPSS Percentile: 🔒

Price Prediction: 🔍
Current Price Estimation: 🔒

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Threat Intelligenceinfo

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

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔒

Upgrade: Webmention Plugin 5.7.0

Timelineinfo

06/01/2026 CVE reserved
07/01/2026 +30 days Advisory disclosed
07/01/2026 +0 days VulDB entry created
07/01/2026 +0 days VulDB entry last update

Sourcesinfo

Advisory: wordfence.com
Researcher: Volodymyr Kolesnykov
Status: Confirmed

CVE: CVE-2026-10513 (🔒)
GCVE (CVE): GCVE-0-2026-10513
GCVE (VulDB): GCVE-100-374905

Entryinfo

Created: 07/01/2026 05:58
Changes: 07/01/2026 05:58 (68)
Complete: 🔍
Cache ID: 216::103

Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

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