VDB-362407 · CVE-2026-42556 · GHSA-hhxq-3wg7-4rj8

gitroomhq postiz-app up to 2.21.6 /p/?share=true cross site scripting

CVSS Meta Temp Score CVSS is a standardized scoring system to determine possibilities of attacks. The Temp Score considers temporal factors like disclosure, exploit and countermeasures. The unique Meta Score calculates the average score of different sources to provide a normalized scoring system.	Current Exploit Price (≈) Our analysts are monitoring exploit markets and are in contact with vulnerability brokers. The range indicates the observed or calculated exploit price to be seen on exploit markets. A good indicator to understand the monetary effort required for and the popularity of an attack.	CTI Interest Score Our Cyber Threat Intelligence team is monitoring different web sites, mailing lists, exploit markets and social media networks. The CTI Interest Score identifies the interest of attackers and the security community for this specific vulnerability in real-time. A high score indicates an elevated risk to be targeted for this vulnerability.
7.1	$0-$5k	0.00

Summaryinfo

A vulnerability has been found in gitroomhq postiz-app up to 2.21.6 and classified as problematic. Affected by this issue is some unknown functionality of the file /p/?share=true. This manipulation causes cross site scripting. This vulnerability is tracked as CVE-2026-42556. The attack is possible to be carried out remotely. No exploit exists. The affected component should be upgraded.

Detailsinfo

A vulnerability has been found in gitroomhq postiz-app up to 2.21.6 and classified as problematic. Affected by this vulnerability is an unknown part of the file /p/?share=true. 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:

Postiz is an AI social media scheduling tool. From version 2.21.6 to before version 2.21.7, any authenticated user who can create a post can store arbitrary HTML in post content by tampering their own save request and send the public preview link /p/<postId>?share=true to another user. The preview page renders that stored HTML with dangerouslySetInnerHTML on the main application origin. This issue has been patched in version 2.21.7.

It is possible to read the advisory at github.com. This vulnerability is known as CVE-2026-42556 since 04/28/2026. The exploitation appears to be easy. The attack can be launched remotely. It demands that the victim is doing some kind of user interaction. Technical details of the vulnerability are known, but there is no available exploit. The attack technique deployed by this issue is T1059.007 according to MITRE ATT&CK.

Upgrading to version 2.21.7 eliminates this vulnerability. The upgrade is hosted for download at github.com.

Be aware that VulDB is the high quality source for vulnerability data.

Productinfo

Vendor

gitroomhq

Name

postiz-app

Version

Website

Product: https://github.com/gitroomhq/postiz-app/

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 7.1
VulDB Meta Temp Score: 7.1

VulDB Base Score: 3.5
VulDB Temp Score: 3.4
VulDB Vector: 🔒
VulDB Reliability: 🔍

NVD Base Score: 9.0
NVD Vector: 🔒

CNA Base Score: 8.9
CNA Vector (GitHub_M): 🔒

CVSSv2info

AV	AC	Au	C	I	A
💳	💳	💳	💳	💳	💳
💳	💳	💳	💳	💳	💳
💳	💳	💳	💳	💳	💳

Vector	Complexity	Authentication	Confidentiality	Integrity	Availability
Unlock	Unlock	Unlock	Unlock	Unlock	Unlock
Unlock	Unlock	Unlock	Unlock	Unlock	Unlock
Unlock	Unlock	Unlock	Unlock	Unlock	Unlock

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: 🔒

0-Day	Unlock	Unlock	Unlock	Unlock
Today	Unlock	Unlock	Unlock	Unlock

Threat Intelligenceinfo

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

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔒

Upgrade: postiz-app 2.21.7

Timelineinfo

04/28/2026 CVE reserved
05/09/2026 +11 days Advisory disclosed
05/09/2026 +0 days VulDB entry created
05/18/2026 +9 days VulDB entry last update

Sourcesinfo

Product: github.com

Advisory: GHSA-hhxq-3wg7-4rj8
Status: Confirmed

CVE: CVE-2026-42556 (🔒)
GCVE (CVE): GCVE-0-2026-42556
GCVE (VulDB): GCVE-100-362407

Entryinfo

Created: 05/09/2026 07:03
Updated: 05/18/2026 23:55
Changes: 05/09/2026 07:03 (66), 05/18/2026 23:55 (12)
Complete: 🔍
Cache ID: 216::103