SB2026040146 - Multiple vulnerabilities in Zulip Server

Description

This security bulletin contains information about 2 vulnerabilities.

1) Missing Authorization (CVE-ID: CVE-2026-25742)

CWE-ID: CWE-862 - Missing Authorization

CVSSv4: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N/E:U/U:Green

The vulnerability allows a remote attacker to gain access to potentially sensitive information.

The vulnerability exists due to missing authorization after disabling spectator access. A remote attacker can gain access to file contents.

2) Path traversal (CVE-ID: CVE-2026-26058)

CWE-ID: CWE-22 - Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')

CVSSv4: CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:A/VC:H/VI:L/VA:N/SC:N/SI:N/SA:N/E:U/U:Green

The vulnerability allows a remote attacker to perform directory traversal attacks.

The vulnerability exists due to input validation error when processing directory traversal sequences in uploads/records.json. A remote attacker can send a specially crafted HTTP request and read arbitrary files on the system.

Remediation

Cybersecurity Help is not aware of any official remediation provided by the vendor.

References

• https://github.com/zulip/zulip/security/advisories/GHSA-f47p-xjqq-g28w
• https://github.com/zulip/zulip/security/advisories/GHSA-xm5c-c6mp-3956