How severe is CVE-2026-25742?

CVE-2026-25742 has a CVSS 3.x base score of 5.3, rated medium severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is low, integrity none, and availability none.

Is CVE-2026-25742 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (23rd percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2026-25742?

CVE-2026-25742 affects Zulip. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2026-25742?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

Does CVE-2026-25742 have an EU (EUVD) identifier?

Yes. CVE-2026-25742 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-18835.

When was CVE-2026-25742 published?

CVE-2026-25742 was published on 2026-04-03 and last updated on 2026-06-17.

CVE-2026-25742

CVE-2026-25742 is a medium-severity vulnerability in Zulip with a CVSS 3.x base score of 5.3. 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-862.

Key facts

Severity: Medium (CVSS 3.x base score 5.3)
EPSS exploit prediction: 0% (23rd percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2026-18835
Weakness: CWE-862
Affected product: Zulip
Published: 2026-04-03
Last modified: 2026-06-17

Description

Zulip is an open-source team collaboration tool. Prior to version 11.6, Zulip is an open-source team collaboration tool. From version 1.4.0 to before version 11.6, even after spectator access (enable_spectator_access / WEB_PUBLIC_STREAMS_ENABLED) is disabled, attachments originating from web-public streams can still be retrieved anonymously. As a result, file contents remain accessible even after public access is intended to be disabled. Similarly, even after spectator access is disabled, the /users/me/<stream_id>/topics endpoint remains reachable anonymously, allowing retrieval of topic history for web-public streams. This issue has been patched in version 11.6. This issue has been patched in version 11.6.

Frequently asked questions

What is CVE-2026-25742?: Zulip is an open-source team collaboration tool. Prior to version 11.6, Zulip is an open-source team collaboration tool. From version 1.4.0 to before version 11.6, even after spectator access (enable_spectator_access / WEB_PUBLIC_STREAMS_ENABLED) is disabled, attachments originating from web-public streams can still be retrieved anonymously. As a result, file contents remain accessible even after public access is intended to be disabled. Similarly, even after spectator access is disabled, the /users/me/<stream_id>/topics endpoint remains reachable anonymously, allowing retrieval of topic history for web-public streams. This issue has been patched in version 11.6. This issue has been patched in version 11.6.
How severe is CVE-2026-25742?: CVE-2026-25742 has a CVSS 3.x base score of 5.3, rated medium severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is low, integrity none, and availability none.
Is CVE-2026-25742 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (23rd percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-25742?: CVE-2026-25742 affects Zulip. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2026-25742?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
Does CVE-2026-25742 have an EU (EUVD) identifier?: Yes. CVE-2026-25742 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-18835.
When was CVE-2026-25742 published?: CVE-2026-25742 was published on 2026-04-03 and last updated on 2026-06-17.

References

Affected products (1)

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

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