Raw vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:NCVSS and EPSS are reproduced from their sources (NVD, FIRST EPSS). Risk Priority is our own derived reading, not an NVD score.
Summary
CVE-2023-31145 is a medium-severity Cross-site Scripting (CWE-79) vulnerability in Collabora Online. Its CVSS base score is 4.3 (Medium).
Operationally, exploitation aligns with the MITRE ATT&CK technique Protocol or Service Impersonation (T1001.003); ranked at the 32th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.
OWASP Top 10 for Web (2025)
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2023-35462
Vulnerability Data
Collabora Online is a collaborative online office suite based on LibreOffice technology. This vulnerability report describes a reflected XSS vulnerability with full CSP bypass in Nextcloud installations using the recommended bundle. The vulnerability can be exploited to perform a trivial…
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account takeover attack. The vulnerability allows attackers to inject malicious code into web pages, which can be executed in the context of the victim's browser session. This means that an attacker can steal sensitive data, such as login credentials or personal information, or perform unauthorized actions on behalf of the victim, such as modifying or deleting data. In this specific case, the vulnerability allows for a trivial account takeover attack. An attacker can exploit the vulnerability to inject code into the victim's browser session, allowing the attacker to take over the victim's account without their knowledge or consent. This can lead to unauthorized access to sensitive information and data, as well as the ability to perform actions on behalf of the victim. Furthermore, the fact that the vulnerability bypasses the Content Security Policy (CSP) makes it more dangerous, as CSP is an important security mechanism used to prevent cross-site scripting attacks. By bypassing CSP, attackers can circumvent the security measures put in place by the web application and execute their malicious code. This issue has been patched in versions 22.05.13, 21.11.9, and 6.4.27. Users are advised to upgrade. There are no known workarounds for this vulnerability.
- CWE(s)
Related Threats
MITRE ATT&CK Enterprise Techniques
CVEs Like This One
Affected Assets
Mitigating Controls
Control response
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V1.1.2V1.3.2
Likely Mitigating Controls AI
Per-CVE control mapping for this CVE has not run yet; the list below is derived from the weakness types (CWEs) cited in the NVD entry.
Penetration testing submits XSS payloads to web applications, detecting cross-site scripting flaws for subsequent remediation.
Validates web inputs to reject script-related content that could produce XSS.
Output validation against expected content can reject or sanitize script content in generated web pages, reducing XSS exploitability.
Mitigating Controls (NIST CSF 2.0) AI
Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.
Secure SDLC practices directly target introduction of XSS via coding standards/testing (mostly), yet the single broad outcome leaves many specific neutralization vectors unaddressed (partial).
Patching and EOL replacement can remediate known XSS instances in libraries or frameworks (partial) but do nothing to enforce input neutralization in application code (none).
Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI
Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.
A.5.6 only promotes membership in groups to improve knowledge, receive alerts, and share information; it performs no action that stops XSS exploitation (or even the underlying neutralization defect) and is a pure dependency for other controls per the owner's labeling rule.