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CVE-2020-13965 CISA KEV — actively exploited

Roundcube Webmail Cross-Site Scripting (XSS) Vulnerability

n/a — n/a

An issue was discovered in Roundcube Webmail before 1.3.12 and 1.4.x before 1.4.5. There is XSS via a malicious XML attachment because text/xml is among the allowed types for a preview.

CVSS scoreMedium

6.3

EPSS — exploitation probabilityHigh

76.6%

Vector breakdown

Attack vector
Network
Attack complexity
Low
Privileges required
None
User interaction
Required
Scope
Unchanged
Confidentiality
Low
Integrity
Low
Availability
Low

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

Published
Jun 9, 2020
Modified
Oct 21, 2025
Added to KEV
Jun 26, 2024
Federal patch due
Jul 17, 2024

CISA required action

Apply mitigations per vendor instructions or discontinue use of the product if mitigations are unavailable.

Weakness classification

Proof-of-concept & exploitation references

Public repositories whose name or description references CVE-2020-13965, found via a live GitHub search at request time. These are community-sourced signals, not a verified working exploit — cross-check each one before relying on it, and treat higher star counts and recent activity as (weak) corroboration, not proof.

No public GitHub repositories referencing CVE-2020-13965 were found at last check. Absence here is not proof no exploit exists — see the references below for vendor advisories and write-ups.

References

Frequently asked questions

What is CVE-2020-13965?

An issue was discovered in Roundcube Webmail before 1.3.12 and 1.4.x before 1.4.5. There is XSS via a malicious XML attachment because text/xml is among the allowed types for a preview.

How severe is CVE-2020-13965?

CVE-2020-13965 has a CVSS base score of 6.3 out of 10 (CVSS 3.1).

Is CVE-2020-13965 actively exploited in the wild?

Yes. CVE-2020-13965 is listed in the CISA Known Exploited Vulnerabilities (KEV) catalog, added Jun 26, 2024, meaning CISA has confirmed evidence of active exploitation.

What is the EPSS score for CVE-2020-13965?

76.6% - meaning FIRST.org's EPSS model estimates a 76.6% probability this vulnerability will be exploited in the wild within 30 days (100% percentile among all scored CVEs).

What type of vulnerability is CVE-2020-13965?

CVE-2020-13965 is classified under CWE-80 (CWE-80 Improper Neutralization of Script-Related HTML Tags in a Web Page (Basic XSS)).

Cross-checked against

Impactr finds and proves whether CVE-2020-13965 — or flaws like it — are actually reachable in your own web apps and APIs, with a reproducible exploit as evidence.