SB2026021336 - Multiple vulnerabilities in Shaarli

Description

This security bulletin contains information about 2 vulnerabilities.

1) Cross-site scripting (CVE-ID: CVE-2025-55291)

CWE-ID: CWE-79 - Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')

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

The disclosed vulnerability allows a remote attacker to perform cross-site scripting (XSS) attacks.

The vulnerability exists due to insufficient sanitization of user-supplied data in the cloud tag page. A remote attacker can trick the victim to follow a specially crafted link and execute arbitrary HTML and script code in user's browser in context of vulnerable website.

Successful exploitation of this vulnerability may allow a remote attacker to steal potentially sensitive information, change appearance of the web page, perform phishing and drive-by-download attacks.

2) Improper Neutralization of Script-Related HTML Tags in a Web Page (Basic XSS) (CVE-ID: N/A)

CWE-ID: CWE-80 - Improper Neutralization of Script-Related HTML Tags in a Web Page (Basic XSS)

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

The vulnerability allows a remote user to execute arbitrary script in the victim's browser.

The vulnerability exists due to improper neutralization of script-related HTML tags in uploaded or embedded filenames in the filename rendering logic when rendering uploaded or embedded filenames in the DOM. A remote user can upload a file with a specially crafted filename to execute arbitrary script in the victim's browser.

The attack vector is limited by rendering context and browser behavior.

Remediation

Install update from vendor's website.

References

• https://github.com/shaarli/Shaarli/commit/66faa61335a6e72184be64092ff1242ffa4fe5b6
• https://github.com/shaarli/Shaarli/security/advisories/GHSA-7w7w-pw4j-265h
• https://github.com/shaarli/Shaarli/security/advisories/GHSA-vwcv-9hj3-8982