Vulnerability Report

CVE-2026-53963

Title: Stored XSS via malicious second factor name in Discourse

XSS

Proof Of Concept

No public PoC currently indexed for CVE-2026-53963.

CWE Category CWE-79
Published Date Jul 09, 2026
Modified Date Jul 14, 2026
Exploit Status Not Found
Score 7.3 CVSS v3.1
Exploit Probability (EPSS)
0.45%

Vulnerability Summary

CVE-2026-53963: Discourse is an open-source discussion platform. Prior to 2026.6.0, 2026.5.1, 2026.4.2, and 2026.1.5, a malicious second factor name on an attacker-controlled account was not escaped in the delete confirmation dialog, allowing stored cross-site scripting when an administrator impersonated that account. This issue is fixed in versions 2026.6.0, 2026.5.1, 2026.4.2, and 2026.1.5.

Impacted Vendors

D
discourse 1

Reference Links

https://github.com/discourse/discourse/commit/40de62cddadc65c328a1028ab999f3fa94adbfed https://github.com/discourse/discourse/commit/529e17d4d570a48972e7cf64720e5dd1fdf23ca8 https://github.com/discourse/discourse/commit/d92973e51a46cf6dd20c71e6068e6769b67eea5b https://github.com/discourse/discourse/commit/daea5214d833eacbdd3b1a78d99eb14e9cabd915 https://github.com/discourse/discourse/releases/tag/v2026.1.5 https://github.com/discourse/discourse/releases/tag/v2026.4.2 https://github.com/discourse/discourse/releases/tag/v2026.5.1 https://github.com/discourse/discourse/releases/tag/v2026.6.0 https://github.com/discourse/discourse/security/advisories/GHSA-wg5x-7f23-m3r5
CVSS v3.1
Source Entity [email protected]
Severity HIGH
7.3
Attack Vector
NETWORK
Complexity
LOW
Privileges
N/A
Interaction
REQUIRED
Confidentiality
N/A
Integrity
N/A
Availability
N/A
Scope
UNCHANGED
RAW VECTOR CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:H/I:H/A:N
CVSS v3.1
Source Entity [email protected]
Severity CRITICAL
9.0
Attack Vector
NETWORK
Complexity
LOW
Privileges
N/A
Interaction
REQUIRED
Confidentiality
N/A
Integrity
N/A
Availability
N/A
Scope
CHANGED
RAW VECTOR CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:H/A:H

Associated Attack Patterns (CAPEC)

Total: Patterns

CVE-2026-53963 Exploits & PoCs (Proof Of Concept)

No public PoCs found in our database for this CVE.

MODIFIED

Vulnerability data updated via NVD.

MODIFIED

Vulnerability data updated via NVD.

MODIFIED

Vulnerability data updated via NVD.

MODIFIED

Vulnerability data updated via NVD.

Attack Vector Matrix

Access Vector NETWORK
Complexity LOW
Privileges N/A
Interaction REQUIRED
CVSS Vector String CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:H/I:H/A:N

Affected Stack

No specific products linked.