CVE-2025-30345: openslides Improper Encoding — Exploit

Description

An issue was discovered in OpenSlides before 4.2.5. When creating new chats via the chat_group.create action, the user is able to specify the name of the chat. Some HTML elements such as SCRIPT are filtered, whereas others are not. In most cases, HTML entities are encoded properly, but not when deleting chats or deleting messages in these chats. This potentially allows attackers to interfere with the layout of the rendered website, but it is unlikely that victims would click on deleted chats or deleted messages.

Is your site exposed to CVE-2025-30345?

Run a free security scan — no signup, results in seconds.

CVSS v3.1 Score

3.5

LOW

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

Weakness Type (CWE)

CWE-116 CWE-116

CWE-79 Cross-site Scripting (XSS)

Affected Products

Vendor	Product	Versions
openslides	openslides	< 4.2.5

References

Exploits

https://www.x41-dsec.de/lab/advisories/x41-2025-001-OpenSlides

Frequently Asked Questions

What is CVE-2025-30345? +

An issue was discovered in OpenSlides before 4.2.5. When creating new chats via the chat_group.create action, the user is able to specify the name of the chat. Some HTML elements such as SCRIPT are filtered, whereas others are not. In most cases, HTML entities are encoded properly, but not when deleting chats or deleting messages in these chats. This potentially allows attackers to interfere with the layout of the rendered website, but it is unlikely that victims would click on deleted chats or deleted messages. It has a CVSS v3.1 base score of 3.5 (LOW).

How severe is CVE-2025-30345? +

CVE-2025-30345 has a CVSS v3.1 score of 3.5 out of 10, rated LOW. This is a low-severity vulnerability with limited impact.

What products are affected by CVE-2025-30345? +

CVE-2025-30345 affects products from openslides, specifically: openslides. Check the affected products table above for specific version ranges.

How do I check if I'm vulnerable to CVE-2025-30345? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

Related Vulnerabilities

CVE-2026-62681

Orval generates type-safe JavaScript clients in TypeScript from OpenAPI v3 and Swagger v2 specifications. Prior to 8.21.0, an unescaped backtick …

CVE-2026-82409

Klever-Go is the Go implementation of the Klever blockchain protocol. Prior to 1.7.20, indexer/common.go serializedDataForUpdateAccounts places the attacker-controlled acc.Name value …

CVE-2026-71864

Orval generates type-safe JavaScript clients in TypeScript from OpenAPI v3 and Swagger v2 specifications. Prior to 8.21.0, a double quote …

CVE-2026-50642

diff‑so‑fancy does not properly sanitize non‑SGR terminal control sequences before outputting diff data. The application only strips ANSI SGR sequences …

CVE-2026-77404

RabbitMQ amqp091-go is a Go AMQP 0.9.1 client. Prior to 1.13.0, URI.String in uri.go concatenates CertFile, KeyFile, CACertFile, and ServerName …

CVE-2026-88921

MISP contains an HTML injection vulnerability in the MISPElementHTMLFormatterTool component, which is responsible for rendering MISP element references (attributes, objects, …

CVE-2025-30345