Critical severity · published Jul 9, 2026
CVE-2026-53963
Discourse: Stored-XSS in 2FA delete confirmation modal
9.0
CVSS
0.7%
EPSS
No
On KEV
Description
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.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:H/A:H
Attack vector
Network
Complexity
Low
Privileges
Low
User interaction
Required
Confidentiality
High
Integrity
High
Availability
High
Scope
Changed
Exploitation
Is it being used?
Exploit prediction (EPSS)0.7% · higher than 54% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
DI
discourse · discourse
>= 2026.1.0-latest, < 2026.1.5; >= 2026.4.0-latest, < 2026.4.2; >= 2026.5.0-latest, < 2026.5.1 · source: vendor, NVD
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-53963
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-53963
Patch
https://github.com/discourse/discourse/commit/40de62cddadc65c328a1028ab999f3fa94adbfed
Patch
https://github.com/discourse/discourse/commit/529e17d4d570a48972e7cf64720e5dd1fdf23ca8
Patch
https://github.com/discourse/discourse/commit/d92973e51a46cf6dd20c71e6068e6769b67eea5b
Patch
https://github.com/discourse/discourse/commit/daea5214d833eacbdd3b1a78d99eb14e9cabd915
Release Notes
https://github.com/discourse/discourse/releases/tag/v2026.1.5
Release Notes
https://github.com/discourse/discourse/releases/tag/v2026.4.2
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