CVE intelligence and bounded remediation

CVE-2026-25741 — Zulip is an open-source team collaboration tool

High CVSS 7.1

Zulip is an open-source team collaboration tool. Prior to commit bf28c82dc9b1f630fa8e9106358771b20a0040f7, the API endpoint for creating a card update session during an upgrade flow was accessible to users with only organization member privileges. When the associated Stripe Checkout session is completed, the Stripe webhook updates the organization’s default payment method. Because no billing-specific authorization check is enforced, a regular (non-billing) member can change the organization’s payment method. This vulnerability affected the Zulip Cloud payment processing system, and has been patched as of commit bf28c82dc9b1f630fa8e9106358771b20a0040f7. Self-hosted deploys are no longer affected and no patch or upgrade is required for them.

Severity
High
CVSS
7.1 (3.1)
Published
2026-02-26
CISA KEV
Not currently listed
Ecosystem
software/application
Weaknesses
CWE-863

Affected products

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Matched remediation archetype

Authorization bypass, IDOR, and cross-tenant access

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Check exposure

  • Map object and action authorization checks across API, UI, batch, import/export, and background-job paths.
  • Identify tenant, ownership, role, and policy boundaries for affected resources and administrative operations.
  • Use synthetic fixtures to compare intended access matrices without accessing another user's real data.

Remediate safely

  • Enforce server-side authorization at each resource access and state transition using the authenticated principal and trusted tenant context.
  • Scope data queries by tenant and ownership; treat client-supplied identifiers, roles, and policy claims as untrusted.
  • Add deny-by-default policy tests for horizontal and vertical access across every affected transport.

Authoritative sources

Complete CVE record and remediation plan

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