Zulip ServerApplication · Zulip

CVE-2026-24050

MEDIUM · 5.4 CVSS v3.1 Published 2026-02-06
Fix available
A fix is available. Upgrade to 11.5 or later.
See remediation →
58/100
Remediation priority · Elevated
Remotely reachable Patch available

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
Zulip is an open-source team collaboration tool. From 5.0 to before 11.5, some administrative actions on the user profile were susceptible to stored XSS in group names or channel names. Exploiting these vulnerabilities required the user explicitly interacting with the problematic object. This vulnerability is fixed in 11.5.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis
How this class of weakness works · CWE-79

Untrusted input is placed into a web page without being neutralised, so an attacker's markup or script executes in another user's browser. That can hijack sessions, capture keystrokes, or silently perform actions as the victim. Fixing it properly means context-aware output encoding everywhere data meets HTML, backed by a content-security policy as a second line of defence.

General guidance for the cross-site scripting (xss) class — the official description and references above are authoritative for this specific CVE. Want a bespoke review and a reviewed fix? Ask our team →

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
Zulip ServerApplication
Affected:>= 5.0, < 11.5

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Network
Complexity
Low
Privileges
Low
User interaction
Required
Scope
Changed
Confidentiality
Low
Integrity
Low
Availability
None

CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Upgrade available Upgrade to 11.5 or later
Fixed in 11.5
Vendor patch github.com →
Recommended fix High confidence

Zulip Server 11.5 or later

  1. 1. Back up your current Zulip Server data and configuration
  2. 2. Consult the official Zulip upgrade documentation at zulip.readthedocs.io for your current version
  3. 3. Upgrade to Zulip Server version 11.5 or later
  4. 4. Verify the upgrade was successful by logging into the admin interface
  5. 5. Test that the administrative actions on user profiles work correctly
  6. 6. Confirm the XSS vulnerability is patched by attempting to create test group/channel names with script content (in a test environment only)

Generated from the published advisory — verify against the referenced sources before acting.

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Scan for this in your stack

Free · runs locally
dbcve dependency scanner

Check whether your project pulls in CVE-2026-24050 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.

References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2026-24050 in production — separate from our analysis above.

No notes yet

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
  • No weaponised exploit code, or anything meant to cause harm
  • No spam, self-promotion, credentials, or personal data