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CVE-2020-35730

6.1, medium Known exploited

Roundcube Webmail Cross-Site Scripting (XSS) Vulnerability

NVD (opens in a new tab) CVE.org (opens in a new tab) CISA KEV catalogue (opens in a new tab)
CVSS
6.1, medium medium CVSS v3.1
EPSS, next 30 days
33% higher than 98.3% of scored CVEs
Exploitation
Confirmed in the wild
Published
28 Dec 20205 years ago

Known exploited

CISA added this to the Known Exploited Vulnerabilities Catalog on 22 Jun 2023. US federal agencies had to remediate by 13 Jul 2023, a deadline that has passed.

Required action. Apply updates per vendor instructions.

Description

An XSS issue was discovered in Roundcube Webmail before 1.2.13, 1.3.x before 1.3.16, and 1.4.x before 1.4.10. The attacker can send a plain text e-mail message, with JavaScript in a link reference element that is mishandled by linkref_addindex in rcube_string_replacer.php.

Details

Vendor
Roundcube and 2 more
Product
Webmail
Weakness
CWE-79 (opens in a new tab)
Status
Analyzed
Updated
17 Jun 2026
Assigner
cve@mitre.org

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

References 10

Patches and fixes 1

Other references 9

1 more

The kind is read from NVD's tags where present and from the shape of the URL otherwise, so treat it as a hint.

Other Roundcube CVEs

Every Roundcube CVE we hold

Same vendor in what we hold, not a known link between the flaws.

  • CVE-2025-68461 RoundCube Webmail Cross-site Scripting Vulnerability KEV EPSS 27% 6.1, medium
  • CVE-2025-49113 RoundCube Webmail Deserialization of Untrusted Data Vulnerability KEV EPSS 99% 8.8, high
  • CVE-2024-42009 RoundCube Webmail Cross-Site Scripting Vulnerability KEV EPSS 83% 9.3, critical
  • CVE-2024-37383 RoundCube Webmail Cross-Site Scripting (XSS) Vulnerability KEV EPSS 73% 6.1, medium
  • CVE-2023-5631 Roundcube Webmail Persistent Cross-Site Scripting (XSS) Vulnerability KEV EPSS 76% 5.4, medium
  • CVE-2023-43770 Roundcube Webmail Persistent Cross-Site Scripting (XSS) Vulnerability KEV EPSS 64% 6.1, medium
  • CVE-2021-44026 Roundcube Webmail SQL Injection Vulnerability KEV EPSS 70% 9.8, critical
  • CVE-2020-13965 Roundcube Webmail Cross-Site Scripting (XSS) Vulnerability KEV EPSS 77% 6.1, medium

Beyond this page

Is CVE-2020-35730 in your network?

This page tells you how dangerous CVE-2020-35730 is out there. Whether it sits on one of your devices, only a scan of your own network can tell. That is what our systems do, every day, for the companies we protect.

CVE-2020-35730 is in the CISA catalogue of exploited vulnerabilities: attackers are already exploiting it.

  • EXYS7600 OCELOT

    Find it before attackers do

    Ocelot scans your network on a schedule and reports every vulnerability it finds by its CVE identifier, with its CVSS score and how many of your hosts are affected. A finding like CVE-2020-35730 comes with the devices to patch.

    Learn more about EXYS7600 OCELOT

  • EXYS7950 KONDRA

    Detect it if it's exploited

    Until the patch is applied, Kondra monitors your network, events and endpoints in real time. It keeps an inventory of the software installed on every endpoint, and its anomaly detection rules flag what an attacker does once inside.

    Learn more about EXYS7950 KONDRA
Check your exposure

Assembled from the NVD 2.0 API, the CISA Known Exploited Vulnerabilities Catalog and FIRST EPSS. Scores are as of our last collection on 18 Oct 2026, not the live upstream state.