VDB-385089 · CVE-2026-16504 · GCVE-0-2026-16504

VPS.org Zulip insecure default initialization of resource

CVSS Meta Temp Score CVSS is a standardized scoring system to determine possibilities of attacks. The Temp Score considers temporal factors like disclosure, exploit and countermeasures. The unique Meta Score calculates the average score of different sources to provide a normalized scoring system.	Current Exploit Price (≈) Our analysts are monitoring exploit markets and are in contact with vulnerability brokers. The range indicates the observed or calculated exploit price to be seen on exploit markets. A good indicator to understand the monetary effort required for and the popularity of an attack.	CTI Interest Score Our Cyber Threat Intelligence team is monitoring different web sites, mailing lists, exploit markets and social media networks. The CTI Interest Score identifies the interest of attackers and the security community for this specific vulnerability in real-time. A high score indicates an elevated risk to be targeted for this vulnerability.
7.3	$0-$5k	1.63+

Summaryinfo

A vulnerability was found in VPS.org Zulip. It has been classified as critical. Affected by this issue is some unknown functionality. Performing a manipulation results in insecure default initialization of resource. This vulnerability is cataloged as CVE-2026-16504. It is possible to initiate the attack remotely. There is no exploit available.

Detailsinfo

A vulnerability was found in VPS.org Zulip (unknown version). It has been classified as critical. This affects an unknown code block. The manipulation with an unknown input leads to a insecure default initialization of resource vulnerability. CWE is classifying the issue as CWE-1188. The product initializes or sets a resource with a default that is intended to be changed by the administrator, but the default is not secure. This is going to have an impact on confidentiality, integrity, and availability. The summary by CVE is:

Deployment of the VPS.org one-click Zulip template deploys a hardcoded application signing key, a default database password ("zulip"), and DISABLE_HTTPS=True.

The advisory is shared at kb.cert.org. This vulnerability is uniquely identified as CVE-2026-16504 since 07/21/2026. The exploitability is told to be easy. It is possible to initiate the attack remotely. No form of authentication is needed for exploitation. Neither technical details nor an exploit are publicly available. The price for an exploit might be around USD $0-$5k at the moment (estimation calculated on 07/31/2026).

There is no information about possible countermeasures known. It may be suggested to replace the affected object with an alternative product.

Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

Productinfo

Vendor

VPS.org

Name

Zulip

CPE 2.3info

🔒

CPE 2.2info

🔒

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 7.3
VulDB Meta Temp Score: 7.3

VulDB Base Score: 7.3
VulDB Temp Score: 7.3
VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv2info

AV	AC	Au	C	I	A
💳	💳	💳	💳	💳	💳
💳	💳	💳	💳	💳	💳
💳	💳	💳	💳	💳	💳

Vector	Complexity	Authentication	Confidentiality	Integrity	Availability
Unlock	Unlock	Unlock	Unlock	Unlock	Unlock
Unlock	Unlock	Unlock	Unlock	Unlock	Unlock
Unlock	Unlock	Unlock	Unlock	Unlock	Unlock

VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Insecure default initialization of resource
CWE: CWE-1188
CAPEC: 🔒
ATT&CK: 🔒

Physical: No
Local: No
Remote: Yes

Availability: 🔒
Status: Not defined
Price Prediction: 🔍
Current Price Estimation: 🔒

0-Day	Unlock	Unlock	Unlock	Unlock
Today	Unlock	Unlock	Unlock	Unlock

Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: no mitigation known
Status: 🔍

0-Day Time: 🔒

Timelineinfo

07/21/2026 CVE reserved
07/31/2026 +10 days Advisory disclosed
07/31/2026 +0 days VulDB entry created
07/31/2026 +0 days VulDB entry last update

Sourcesinfo

Advisory: kb.cert.org
Status: Not defined

CVE: CVE-2026-16504 (🔒)
GCVE (CVE): GCVE-0-2026-16504
GCVE (VulDB): GCVE-100-385089

Entryinfo

Created: 07/31/2026 17:59
Changes: 07/31/2026 17:59 (50)
Complete: 🔍
Cache ID: 216::103