How severe is CVE-2025-31478?

CVE-2025-31478 has a CVSS 3.x base score of 8.2, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity low, and availability none.

Is CVE-2025-31478 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (25th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2025-31478?

CVE-2025-31478 affects Zulip Zulip Server. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2025-31478?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.

Does CVE-2025-31478 have an EU (EUVD) identifier?

Yes. CVE-2025-31478 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2025-11790.

When was CVE-2025-31478 published?

CVE-2025-31478 was published on 2025-04-16 and last updated on 2026-06-17.

CVE-2025-31478

CVE-2025-31478 is a high-severity vulnerability in Zulip Zulip Server with a CVSS 3.x base score of 8.2. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-287.

Key facts

Severity: High (CVSS 3.x base score 8.2)
EPSS exploit prediction: 0% (25th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2025-11790
Weakness: CWE-287
Affected product: Zulip Zulip Server
Published: 2025-04-16
Last modified: 2026-06-17

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.

Frequently asked questions

What is CVE-2025-31478?: 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.
How severe is CVE-2025-31478?: CVE-2025-31478 has a CVSS 3.x base score of 8.2, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity low, and availability none.
Is CVE-2025-31478 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (25th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2025-31478?: CVE-2025-31478 affects Zulip Zulip Server. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2025-31478?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
Does CVE-2025-31478 have an EU (EUVD) identifier?: Yes. CVE-2025-31478 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2025-11790.
When was CVE-2025-31478 published?: CVE-2025-31478 was published on 2025-04-16 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:a:zulip:zulip_server:*:*:*:*:*:*:*:*

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