CVE-2020-13965: Roundcube Webmail Cross-Site Scripting (XSS) Vulnerability
- Is it exploited?
Yes. CISA added it to the Known Exploited Vulnerabilities catalog on 26 Jun 2024, 1,478 days after the CVE record was published.
- How likely is exploitation in the next 30 days?
- 76.6%
EPSS score, percentile 99.5 of all scored records
- How severe?
- 6.3 Medium
CVSS v3.1 base score, from CISA's enrichment of the record
- What should I do?
Required action (CISA), due 17 Jul 2024: Apply mitigations per vendor instructions or discontinue use of the product if mitigations are unavailable.
- Which versions are affected?
Not stated. The CVE record gives vendor and product as “n/a” and the version as “unspecified”.
Source: CISA Known Exploited Vulnerabilities (KEV) catalog, 2026.10.28, as of 28 Oct 2026; FIRST Exploit Prediction Scoring System (EPSS), v2026.06.15, as of 28 Oct 2026; CVE List V5 (CVE Program), cve_2026-10-28_0000Z, as of 28 Oct 2026. About the data.
What to do
Required action, set by CISA
Apply mitigations per vendor instructions or discontinue use of the product if mitigations are unavailable.
CISA due date for this action: 17 July 2024.
Advisories and patches
Linked from CISA's catalog entry
- https://roundcube.net/news/2020/06/02/security-updates-1.4.5-and-1.3.12
- https://nvd.nist.gov/vuln/detail/CVE-2020-13965
Affected products and versions
The CVE record does not name affected products or versions: vendor and product are “n/a” and the version is “unspecified”.
Source: CVE List V5 (CVE Program), cve_2026-10-28_0000Z, as of 28 Oct 2026. About the data.
About this vulnerability
Roundcube Webmail contains a cross-site scripting (XSS) vulnerability that allows a remote attacker to manipulate data via a malicious XML attachment.
Summary: CISA's KEV catalog, as of 28 Oct 2026.
- CISA added CVE-2020-13965 to its Known Exploited Vulnerabilities (KEV) catalog on 26 Jun 2024.
- CISA's ransomware flag for this entry is "Unknown": no evidence of ransomware use in the catalog, which is not proof of none.
- The due date CISA sets for the required action is 17 Jul 2024.
- The CVE record was published on 9 Jun 2020, 1,478 days before it was added to KEV.
- The CVE record carries a CVSS v3.1 base score of 6.3 (Medium), taken from CISA's enrichment of the record.
- FIRST's EPSS model puts the probability of exploitation in the next 30 days at 76.6% (percentile 99.5), as of 28 Oct 2026.
- CISA's SSVC assessment in the CVE record: exploitation active, automatable no, technical impact partial.
Source: CISA Known Exploited Vulnerabilities (KEV) catalog, 2026.10.28, as of 28 Oct 2026; CVE List V5 (CVE Program), cve_2026-10-28_0000Z, as of 28 Oct 2026; FIRST Exploit Prediction Scoring System (EPSS), v2026.06.15, as of 28 Oct 2026. About the data.
Description
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.
Source: CVE List V5 (CVE Program), cve_2026-10-28_0000Z, as of 28 Oct 2026. About the data.
Weakness
- CWE-80: Improper Neutralization of Script-Related HTML Tags in a Web Page (Basic XSS)
CWE and CAPEC are maintained by MITRE; the entries are those named in the CVE record and the KEV entry.
Timeline
| Date | Event |
|---|---|
| 9 Jun 2020 | CVE record published |
| 26 Jun 2024 | Added to CISA KEV |
| 17 Jul 2024 | CISA due date for the required action |
| 21 Oct 2025 | CVE record last updated |
References
More exploited Roundcube vulnerabilities
- CVE-2025-49113: RoundCube Webmail Deserialization of Untrusted Data Vulnerability
- CVE-2025-68461: RoundCube Webmail Cross-site Scripting Vulnerability
- CVE-2024-42009: RoundCube Webmail Cross-Site Scripting Vulnerability
- CVE-2024-37383: RoundCube Webmail Cross-Site Scripting (XSS) Vulnerability
- CVE-2023-43770: Roundcube Webmail Persistent Cross-Site Scripting (XSS) Vulnerability
- CVE-2023-5631: Roundcube Webmail Persistent Cross-Site Scripting (XSS) Vulnerability