Zulip is an open-source team collaboration tool. From 5.0 to before 11.5, some administrative actions on the user profile were susceptible to stored XSS in group names or channel names. Exploiting these vulnerabilities required the user explicitly interacting with the problematic object. This vulnerability is fixed in 11.5.
https://zulip.readthedocs.io/en/latest/overview/changelog.html#zulip-server-11-5
https://github.com/zulip/zulip/security/advisories/GHSA-56qv-8823-6fq9
https://github.com/zulip/zulip/releases/tag/11.5
https://github.com/zulip/zulip/commit/e6093d9e4788f4d82236d856c5ed7b16767886a7
Published: 2026-02-06
Updated: 2026-02-23
Base Score: 5.5
Vector: CVSS2#AV:N/AC:L/Au:S/C:P/I:P/A:N
Severity: Medium
Base Score: 5.4
Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N
Severity: Medium
Base Score: 4.8
Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:P/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N
Severity: Medium
EPSS: 0.00043