Improper Authentication in Zulip Server
| Risk | High |
| Patch available | YES |
| Number of vulnerabilities | 1 |
| CVE-ID | CVE-2025-31478 |
| CWE-ID | CWE-287 |
| Exploitation vector | Network |
| Public exploit | N/A |
| Vulnerable software |
Zulip Server Web applications / Other software |
| Vendor | Zulip |
Security Bulletin
This security bulletin contains one high risk vulnerability.
1) Improper Authentication
EUVDB-ID: #VU107580
Risk: High
CVSSv4.0: 6.7 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:L/VA:N/SC:N/SI:N/SA:N/E:U/U:Amber]
CVE-ID: CVE-2025-31478
CWE-ID:
CWE-287 - Improper Authentication
Exploit availability: No
DescriptionThe vulnerability allows a remote attacker to bypass authentication process.
The vulnerability exists due to authentication backend configuration bypass. A remote attacker can create an account without having an account with the configured SSO authentication backend.
MitigationInstall updates from vendor's website.
Vulnerable software versionsZulip Server: 10.0 - 10.1
CPE2.3 External linkshttps://github.com/zulip/zulip/security/advisories/GHSA-qxfv-j6vg-5rqc
Q & A
Can this vulnerability be exploited remotely?
Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the Internet.
Is there known malware, which exploits this vulnerability?
No. We are not aware of malware exploiting this vulnerability.
