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TI-2026-20810 Aliases CVE-2026-25742

Zulip: Anonymous File Access After Disabling Spectator Access

Priority MEDIUM 63CWE-862Published · Updated

Key facts

Attack vector
Network
Privileges required
None
User interaction
None
Attack complexity
Low
Impact type
Security bypass
Confidentiality · integrity · availability
Low · None · None
Fix status
Fixed

Attack profile from CVSS 3.1 · CNA. Fix status from CNA. Impact type from CWE-862.

Summary

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.

Why it matters now

Exploitation Proof of concept CISA SSVC · not in CISA KEV
EPSS 0.00324 25th percentileScored 2026-11-07
Public exploit Yes 1 exploit referenceTagged by NVD
Fix Fixed zulip (zulip): 11.6

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
Poc
Automatable
Yes
Technical impact
Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
zulipzulipbefore 11.611.6Patch availableCNA
  • zulip Vendorzulip Affected before 11.6 Fixed in 11.6 Patch available CNA

CPE configurations NVD · 1

CPEVersionsRoleVendor
cpe:2.3:a:zulip:zulip:*:*:*:*:*:*:*:*1.4.0 to before 11.6Vulnerablezulip
  • cpe:2.3:a:zulip:zulip:*:*:*:*:*:*:*:* Versions 1.4.0 to before 11.6 Vulnerable ·zulip

Remediation

  • Fix · CNA zulip (zulip) Fixed in 11.6

Timeline

  1. 2026-10-02 Threatist record created from CVE-2026-25742

References

Exploit 1

Patch 2

Other 1

  • TI-2026-21062 Zulip: Path Traversal in Import CVSS 3.1MEDIUM 6.1
  • TI-2021-19605 RabbitMQ exposes ports with weak default secrets in Zulip Server CVSS 3.1CRITICAL 9.8
  • TI-2023-15953 Users who can send invitations can erroneously add users to streams during invitation in Zulip CVSS 3.1LOW 3.1
  • TI-2022-13210 Zulip Server insufficient authorization for changing bot roles CVSS 3.1HIGH 8.8
  • TI-2021-02864 Improper Access Control in zulip/zulip CVSS 3.1HIGH 8.8
  • TI-2022-16387 Crafted link in Zulip message can cause disclosure of credentials CVSS 3.1HIGH 8.0
See all 19 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences