Discourse up to 2026.1.1/2026.2.0/2026.3.0-latest Content Security Policy cross site scripting

CVSS Meta Temp Score
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CTI Interest Score
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4.7$0-$5k0.00

Summaryinfo

A vulnerability categorized as problematic has been discovered in Discourse up to 2026.1.1/2026.2.0/2026.3.0-latest. The impacted element is an unknown function of the component Content Security Policy Handler. Such manipulation leads to cross site scripting. This vulnerability is traded as CVE-2026-33411. The attack may be launched remotely. There is no exploit available. It is advisable to upgrade the affected component.

Detailsinfo

A vulnerability was found in Discourse up to 2026.1.1/2026.2.0/2026.3.0-latest. It has been rated as problematic. Affected by this issue is an unknown functionality of the component Content Security Policy Handler. 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:

Discourse is an open-source discussion platform. Versions prior to 2026.3.0-latest.1, 2026.2.1, and 2026.1.2 have a potential stored XSS in topic titles for the solved posts stream. Versions 2026.3.0-latest.1, 2026.2.1, and 2026.1.2 contain a patch. As a workaround, ensure that the Content Security Policy is enabled, and has not been modified in a way which would make it more vulnerable to XSS attacks.

The advisory is shared for download at github.com. This vulnerability is handled as CVE-2026-33411 since 03/19/2026. The exploitation is known to be easy. The attack may be launched remotely. Successful exploitation requires user interaction by the victim. There are neither technical details nor an exploit publicly available. The MITRE ATT&CK project declares the attack technique as T1059.007.

Upgrading to version 2026.1.2 or 2026.2.1 eliminates this vulnerability.

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Productinfo

Type

Name

Version

License

Website

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 4.8
VulDB Meta Temp Score: 4.7

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

NVD Base Score: 5.4
NVD Vector: 🔒

CNA Base Score: 5.4
CNA Vector (GitHub_M): 🔒

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

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: Discourse 2026.1.2/2026.2.1

Timelineinfo

03/19/2026 CVE reserved
03/21/2026 +2 days Advisory disclosed
03/21/2026 +0 days VulDB entry created
03/27/2026 +6 days VulDB entry last update

Sourcesinfo

Product: github.com

Advisory: GHSA-j3mm-ghh2-83x2
Status: Confirmed

CVE: CVE-2026-33411 (🔒)
GCVE (CVE): GCVE-0-2026-33411
GCVE (VulDB): GCVE-100-352304

Entryinfo

Created: 03/21/2026 08:13
Updated: 03/27/2026 08:21
Changes: 03/21/2026 08:13 (65), 03/27/2026 08:21 (12)
Complete: 🔍
Cache ID: 216::103

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