CVE-2020-35730

Name: CVE-2020-35730
Creator: NVD / NIST
Published: 2020-12-28T20:15:13.15+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

MEDIUMCVSS 6.1/10Actively ExploitedEPSS 32.37%

Last modified Jun 17, 2026

CVE-2020-35730 is a medium-severity vulnerability rated 6.1/10 on the CVSS scale. 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.. CISA has confirmed active exploitation in the wild. EPSS estimates a 32.37% chance of exploitation in the next 30 days.

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.

Metrics

CVSS 3.1

6.1/10

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

EPSS Probability

32.37%

98.1th percentile

Probability of exploitation in the next 30 days. Learn more

Exploitation Status

This vulnerability is listed in CISA’s Known Exploited Vulnerabilities catalog, confirming active exploitation in the wild. Federal agencies must remediate by Jul 13, 2023.

Weakness Enumeration

Affected Software

Vendor	Product	Versions
Roundcube	Webmail	< 1.2.13
Roundcube	Webmail	>= 1.3.0, < 1.3.16
Roundcube	Webmail	>= 1.4, < 1.4.10
Fedoraproject	Fedora	32
Fedoraproject	Fedora	33
Debian	Debian Linux	9.0

References

https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=978491Issue Tracking, Mailing List
https://github.com/roundcube/roundcubemail/compare/1.4.9...1.4.10Patch
https://github.com/roundcube/roundcubemail/releases/tag/1.2.13Release Notes
https://github.com/roundcube/roundcubemail/releases/tag/1.3.16Release Notes
https://github.com/roundcube/roundcubemail/releases/tag/1.4.10Release Notes
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/HCEU4BM5WGIDJWP6Z4PCH62ZMH57QYM2/Mailing List, Release Notes
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/HMLIZWKMTRCLU7KZLEQHELS4INXJ7X5Q/Mailing List, Release Notes
https://roundcube.net/download/Product
https://www.alexbirnberg.com/roundcube-xss.htmlBroken Link
https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=978491Issue Tracking, Mailing List
https://github.com/roundcube/roundcubemail/compare/1.4.9...1.4.10Patch
https://github.com/roundcube/roundcubemail/releases/tag/1.2.13Release Notes
https://github.com/roundcube/roundcubemail/releases/tag/1.3.16Release Notes
https://github.com/roundcube/roundcubemail/releases/tag/1.4.10Release Notes
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/HCEU4BM5WGIDJWP6Z4PCH62ZMH57QYM2/Mailing List, Release Notes
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/HMLIZWKMTRCLU7KZLEQHELS4INXJ7X5Q/Mailing List, Release Notes
https://roundcube.net/download/Product
https://www.alexbirnberg.com/roundcube-xss.htmlBroken Link
https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2020-35730US Government Resource

Timeline

Published: Dec 28, 2020
Last Modified: Jun 17, 2026
Status: Analyzed

Frequently Asked Questions

What is CVE-2020-35730?

How severe is CVE-2020-35730?

CVE-2020-35730 has a CVSS score of 6.1/10 (MEDIUM severity). The EPSS model estimates a 32.37% probability of exploitation in the next 30 days. This vulnerability is listed in CISA's Known Exploited Vulnerabilities catalog.

How do I fix CVE-2020-35730?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2020-35730?

Run a free Strix scan to check your systems for this vulnerability.

Scan your code now

Source: NVD / NIST