Mateusz Mandera

8 exploits Active since Nov 2019
CVE-2026-26058 WRITEUP MEDIUM WRITEUP
Zulip: Path Traversal in Import
Zulip is an open-source team collaboration tool. From version 1.4.0 to before version 11.6, ./manage.py import reads arbitrary files from the server filesystem via path traversal in uploads/records.json. A crafted export tarball causes the server to copy any file the zulip user can read into the uploads directory during import. This issue has been patched in version 11.6.
CVSS 6.1
CVE-2019-18933 WRITEUP CRITICAL WRITEUP
Zulip Server <2.0.7 - Privilege Escalation
In Zulip Server versions from 1.7.0 to before 2.0.7, a bug in the new user signup process meant that users who registered their account using social authentication (e.g., GitHub or Google SSO) in an organization that also allows password authentication could have their personal API key stolen by an unprivileged attacker, allowing nearly full access to the user's account.
CVSS 9.8
CVE-2021-3967 WRITEUP HIGH WRITEUP
zulip < 4.10 - Improper Access Control
Improper Access Control in GitHub repository zulip/zulip prior to 4.10.
CVSS 8.8
CVE-2021-43791 WRITEUP MEDIUM WRITEUP
Zulip < 4.8 - Insufficient Session Expiration in Account Registration Flow
Zulip is an open source group chat application that combines real-time chat with threaded conversations. In affected versions expiration dates on the confirmation objects associated with email invitations were not enforced properly in the new account registration flow. A confirmation link takes a user to the check_prereg_key_and_redirect endpoint, before getting redirected to POST to /accounts/register/. The problem was that validation was happening in the check_prereg_key_and_redirect part and not in /accounts/register/ - meaning that one could submit an expired confirmation key and be able to register. The issue is fixed in Zulip 4.8. There are no known workarounds and users are advised to upgrade as soon as possible.
CVSS 6.5
CVE-2022-21706 WRITEUP HIGH WRITEUP
Zulip Server 2.0.0-4.10.0 - Insufficient Access Control via Multi-Use Invitations
Zulip is an open-source team collaboration tool with topic-based threading. Zulip Server version 2.0.0 and above are vulnerable to insufficient access control with multi-use invitations. A Zulip Server deployment which hosts multiple organizations is vulnerable to an attack where an invitation created in one organization (potentially as a role with elevated permissions) can be used to join any other organization. This bypasses any restrictions on required domains on users' email addresses, may be used to gain access to organizations which are only accessible by invitation, and may be used to gain access with elevated privileges. This issue has been patched in release 4.10. There are no known workarounds for this issue. ### Patches _Has the problem been patched? What versions should users upgrade to?_ ### Workarounds _Is there a way for users to fix or remediate the vulnerability without upgrading?_ ### References _Are there any links users can visit to find out more?_ ### For more information If you have any questions or comments about this advisory, you can discuss them on the [developer community Zulip server](https://zulip.com/developer-community/), or email the [Zulip security team](mailto:[email protected]).
CVSS 7.2
CVE-2023-28623 WRITEUP MEDIUM WRITEUP
Zulip < 6.2 - Unauthenticated Account Creation via LDAP Authentication Bypass
Zulip is an open-source team collaboration tool with unique topic-based threading. In the event that 1: `ZulipLDAPAuthBackend` and an external authentication backend (any aside of `ZulipLDAPAuthBackend` and `EmailAuthBackend`) are the only ones enabled in `AUTHENTICATION_BACKENDS` in `/etc/zulip/settings.py` and 2: The organization permissions don't require invitations to join. An attacker can create a new account in the organization with an arbitrary email address in their control that's not in the organization's LDAP directory. The impact is limited to installations which have this specific combination of authentication backends as described above in addition to having `Invitations are required for joining this organization` organization permission disabled. This issue has been addressed in version 6.2. Users are advised to upgrade. Users unable to upgrade may enable the `Invitations are required for joining this organization` organization permission to prevent this issue.
CVSS 6.5
CVE-2024-56136 WRITEUP MEDIUM WRITEUP
Zulip Server 7.0-9.4 - Unauthenticated Email Address Enumeration
Zulip server provides an open-source team chat that helps teams stay productive and focused. Zulip Server 7.0 and above are vulnerable to an information disclose attack, where, if a Zulip server is hosting multiple organizations, an unauthenticated user can make a request and determine if an email address is in use by a user. Zulip Server 9.4 resolves the issue, as does the `main` branch of Zulip Server. Users are advised to upgrade. There are no known workarounds for this issue.
CVSS 5.3
CVE-2025-31478 WRITEUP HIGH WRITEUP
Zulip Server < 10.2 - Unauthenticated Account Creation via SSO Bypass
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.
CVSS 8.2