Vulnerability · Published Apr 16, 2025 · Assigned by GitHub_M

CVE-2025-31478Zulip Authentication Backend Configuration Bypass

High 8.2

In plain English

A high-severity improper authentication in zulip from zulip. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.4% (higher than 30% of all known vulnerabilities).

Severity (CVSS 3.1)8.2High

Exploit odds (30 days)0.4%top 69.9% of all CVEs

Exploited in the wildNo reportsCISA SSVC: none

Attack toolingNoneno public tooling known

Official description

Zulip is an open-source team collaboration tool. Zulip supports a configuration where account creation is limited solely by being able to authenticate with a single-sign on authentication backend, meaning the organization places no restrictions on email address domains or invitations being required to join, but has disabled the EmailAuthBackend that is used for email/password authentication. A bug in the Zulip server means that it is possible to create an account in such organizations, without having an account with the configured SSO authentication backend. This issue is patched in version 10.2. A workaround includes requiring invitations to join the organization prevents the vulnerability from being accessed.

Affected products (as reported)

Vendor	Product	Versions
zulip	zulip	< 10.2

Weakness: CWE-287 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:L/A:N

References

https://github.com/zulip/zulip/security/advisories/GHSA-qxfv-j6vg-5rqc x_refsource_CONFIRM
https://github.com/zulip/zulip/commit/b5ab90aaa4a7efdcbf886cb9e7d55fa5bfca3a28 x_refsource_MISC