VDB-377345 · CVE-2026-49256 · GCVE-0-2026-49256

Discourse up to 2026.1.4/2026.4.1/2026.5.0 Tag Management improper authorization

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.
5.1	$0-$5k	0.56

Summaryinfo

A vulnerability has been found in Discourse up to 2026.1.4/2026.4.1/2026.5.0 and classified as problematic. Affected by this issue is some unknown functionality of the component Tag Management. The manipulation leads to improper authorization. This vulnerability is referenced as CVE-2026-49256. Remote exploitation of the attack is possible. No exploit is available.

Detailsinfo

A vulnerability, which was classified as problematic, has been found in Discourse up to 2026.1.4/2026.4.1/2026.5.0. This issue affects an unknown part of the component Tag Management. The manipulation with an unknown input leads to a improper authorization vulnerability. Using CWE to declare the problem leads to CWE-285. The product does not perform or incorrectly performs an authorization check when an actor attempts to access a resource or perform an action. Impacted is confidentiality. The summary by CVE is:

Discourse is an open-source discussion platform. Prior to 2026.6.0, 2026.5.1, 2026.4.2, and 2026.1.5, restricted tag and tag-group names attached to publicly readable categories as allowed_tags, allowed_tag_groups, or required tag groups could leak to anonymous and unauthorized users through category and group endpoints. This issue is fixed in versions 2026.6.0, 2026.5.1, 2026.4.2, and 2026.1.5.

The advisory is shared at github.com. The identification of this vulnerability is CVE-2026-49256 since 05/28/2026. The exploitation is known to be easy. The attack may be initiated remotely. No form of authentication is needed for a successful exploitation. Neither technical details nor an exploit are publicly available. MITRE ATT&CK project uses the attack technique T1548.002 for this issue.

Upgrading to version 2026.1.5, 2026.4.2, 2026.5.1 or 2026.6.0 eliminates this vulnerability.

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

Productinfo

Type

Chat Software

Name

Discourse

Version

License

open-source

Website

Product: https://github.com/discourse/discourse/

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 5.3
VulDB Meta Temp Score: 5.1

VulDB Base Score: 5.3
VulDB Temp Score: 5.1
VulDB Vector: 🔒
VulDB Reliability: 🔍

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: Improper authorization
CWE: CWE-285 / CWE-266
CAPEC: 🔒
ATT&CK: 🔒

Physical: No
Local: No
Remote: Yes

Availability: 🔒
Status: Not defined
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: no mitigation known
Status: 🔍

0-Day Time: 🔒

Upgrade: Discourse 2026.1.5/2026.4.2/2026.5.1/2026.6.0

Timelineinfo

05/28/2026 CVE reserved
07/09/2026 +42 days VulDB entry created
07/10/2026 +0 days Advisory disclosed
07/10/2026 +0 days VulDB entry last update

Sourcesinfo

Product: github.com

Advisory: github.com
Status: Confirmed

CVE: CVE-2026-49256 (🔒)
GCVE (CVE): GCVE-0-2026-49256
GCVE (VulDB): GCVE-100-377345

Entryinfo

Created: 07/10/2026 00:44
Changes: 07/10/2026 00:44 (53)
Complete: 🔍
Cache ID: 216::103