CVE-2023-5631: Roundcube Webmail Persistent Cross-Site Scripting (XSS) Vulnerability
- Is it exploited?
Yes. CISA added it to the Known Exploited Vulnerabilities catalog on 26 Oct 2023, 8 days after the CVE record was published.
- How likely is exploitation in the next 30 days?
- 76.3%
EPSS score, percentile 99.5 of all scored records
- How severe?
- 6.1 Medium
CVSS v3.1 base score, given by the CNA
- What should I do?
CISA deadline 16 Nov 2023. Apply mitigations per vendor instructions or discontinue use of the product if mitigations are unavailable.
The CVE record links no vendor advisory, patch or mitigation.
- Which versions are affected?
Affected
- from 1.6.0 to before 1.6.3
- from 1.5.0 to before 1.5.4
- from 1.4.0 to before 1.5.14
Unaffected 1.6.4; 1.5.5; 1.5.15
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: 16 November 2023.
Advisories and patches
The CVE record links no vendor advisory, patch or mitigation.
Linked from CISA's catalog entry
- https://roundcube.net/news/2023/10/16/security-update-1.6.4-released
- https://roundcube.net/news/2023/10/16/security-updates-1.5.5-and-1.4.15
- https://nvd.nist.gov/vuln/detail/CVE-2023-5631
Affected products and versions
As listed in the CVE record.
| Status | Versions |
|---|---|
| Affected | from 1.6.0 to before 1.6.3 |
| Affected | from 1.5.0 to before 1.5.4 |
| Affected | from 1.4.0 to before 1.5.14 |
| Unaffected | 1.6.4 |
| Unaffected | 1.5.5 |
| Unaffected | 1.5.15 |
Versions not listed are: unaffected.
Versions the record lists as unaffected: 1.6.4, 1.5.5, 1.5.15.
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 persistent cross-site scripting (XSS) vulnerability that allows a remote attacker to run malicious JavaScript code.
Summary: CISA's KEV catalog, as of 28 Oct 2026.
- CISA added CVE-2023-5631 to its Known Exploited Vulnerabilities (KEV) catalog on 26 Oct 2023.
- 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 16 Nov 2023.
- The CVE record was published on 18 Oct 2023, 8 days before it was added to KEV.
- The CVE record carries a CVSS v3.1 base score of 6.1 (Medium), given by its CNA.
- FIRST's EPSS model puts the probability of exploitation in the next 30 days at 76.3% (percentile 99.5), as of 28 Oct 2026.
- CISA's SSVC assessment in the CVE record: exploitation active, automatable no, technical impact total.
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
Stored XSS vulnerability in Roundcube
Roundcube before 1.4.15, 1.5.x before 1.5.5, and 1.6.x before 1.6.4 allows stored XSS via an HTML e-mail message with a crafted SVG document because of program/lib/Roundcube/rcube_washtml.php behavior. This could allow a remote attacker to load arbitrary JavaScript code.
Source: CVE List V5 (CVE Program), cve_2026-10-28_0000Z, as of 28 Oct 2026. About the data.
Weakness
- CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
Attack patterns (CAPEC)
- CAPEC-592: Stored XSS
CWE and CAPEC are maintained by MITRE; the entries are those named in the CVE record and the KEV entry.
Timeline
| Date | Event |
|---|---|
| 18 Oct 2023 | CVE record published |
| 26 Oct 2023 | Added to CISA KEV |
| 16 Nov 2023 | CISA due date for the required action |
| 21 Oct 2025 | CVE record last updated |
References
- github.com
- github.com
- github.com
- github.com
- github.com
- roundcube.net
- github.com
- roundcube.net
- bugs.debian.org
- debian.org
- lists.debian.org
- openwall.com
3 more in the CVE record.
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-2020-13965: Roundcube Webmail Cross-Site Scripting (XSS) Vulnerability
- CVE-2023-43770: Roundcube Webmail Persistent Cross-Site Scripting (XSS) Vulnerability