In Roundcube Webmail before 1.6.18 and 1.7.x before 1.7.3, the modoboa driver of the password plugin could leak a Modoboa API authentication token to a user-controlled host via crafted session data. This issue only affects Roundcube instances using the password plugin with its modoboa driver.

In Roundcube Webmail before 1.6.18 and 1.7.x before 1.7.3, the LDAP search filter was subject to injection via unescaped %u/%fu/%d substitution, which may lead to information disclosure or privilege escalation.

In Roundcube Webmail before 1.6.18 and 1.7.x before 1.7.3, insufficient Cascading Style Sheets (CSS) sanitization in HTML e-mail messages may lead to SSRF or Information Disclosure, e.g., if stylesheet links point to local network hosts. This issue exists because of insufficient fixes for CVE-2026-35540, CVE-2026-48843 and CVE-2026-62643.

In Roundcube Webmail before 1.6.18 and 1.7.x before 1.7.3, improper rule name quoting could lead to managesievedisabledactions setting bypass via a crafted rule name in a Sieve script. This issue only affects Roundcube instances using the managesieve plugin.

In Roundcube Webmail before 1.6.18 and 1.7.x before 1.7.3, an unclosed url() in a FuncIRI attribute of an SVG image could evade the remote image blocking, which may lead to information disclosure or privilege escalation.

In Roundcube Webmail before 1.6.18 and 1.7.x before 1.7.3, mail search and LITERAL+ byte-count desynchronization could lead to information disclosure or privilege escalation via IMAP command injection.

In Roundcube Webmail before 1.6.18 and 1.7.x before 1.7.3, improper HTML/CSS sanitization of the SVG animate "by" attribute may lead to remote image blocking bypass, which in turn may lead to information disclosure or privilege escalation.

In Roundcube Webmail before 1.6.18 and 1.7.x before 1.7.3, the "Add to address book" action was subject to stored XSS.

In Roundcube Webmail before 1.6.18 and 1.7.x before 1.7.3, responses from the CSS (Cascading Style Sheets) proxy were not validated, which may result in information disclosure or XSS (cross-site scripting) via MIME sniffing.

In Roundcube Webmail before 1.6.18 and 1.7.x before 1.7.3, the cmdlearn driver of the markasjunk plugin is subject to remote code execution via crafted placeholder replacement values. This issue only affects Roundcube instances using the markasjunk plugin with its cmdlearn driver.

Roundcube Webmail before 1.6.17 and 1.7.x before 1.7.2 allows Stored Cross-Site Scripting (XSS). The issue occurs because the attachment MIME type is not properly escaped on the attachment-validation warning page.

In Roundcube Webmail before 1.6.17 and 1.7.x before 1.7.2, there is Stored Cross-Site Scripting (XSS) via a crafted plain-text email message. The attacker-controlled JavaScript executes within the victim's authenticated session simply by opening or previewing the message (zero-click).

In Roundcube Webmail before 1.6.17 and 1.7.x before 1.7.2, the password plugin of the Roundcube Webmail was subject to username spoofing via session data, which could lead to account takeover.

In Roundcube Webmail before 1.6.17 and 1.7.x before 1.7.2, insufficient Cascading Style Sheets (CSS) sanitization in HTML e-mail messages may lead to SSRF or Information Disclosure, e.g., if stylesheet links point to local network hosts. NOTE: this issue exists because of insufficient fixes for CVE-2026-35540 and CVE-2026-48843.

In Roundcube Webmail before 1.6.17 and 1.7.x before 1.7.2, an infinite loop was discovered in the TNEF decoder, which may lead to denial of service upon opening an email with a TNEF attachment.

In Roundcube Webmail before 1.6.17 and 1.7.x before 1.7.2, the TNEF decoder was subject to denial of service via a crafted compressed-RTF size.

Roundcube, a webmail frontend, released versions 1.6.16 and 1.7.1 on May 24 that fix a variety of vulnerabilities. From the announcement <https://roundcube.net/news/2026/05/24/security-updates-1.6.16-and-1.7.1>:

Fix stored XSS/HTML/CSS injection in subject field of the draft restore dialog, reported by zazy Fix CSS injection bypass in HTML sanitizer via SVG <animate attributeName="style">, reported by wooseokdotkim Fix pre-auth SQL injection in virtuserquery plugin via pregreplace backslash escape bypass, reported by skull Fix SSRF bypass via specific local address URLs Fix local/private URL fetch bypass when remote resources were not allowed, reported by Orange Cyberdefense Vulnerability Disclosure Team Fix bypass of remote image blocking via CSS var(), reported by Geame Fix pre-auth arbitrary file delete via redis/memcache session poisoning bypass, reported by valent1 Fix code injection vulnerability - remove support for code evaluation in LDAP autovalues option, reported by Glendaenri As usual, CVE numbers are not provided in the announcement. See for example <https://security-tracker.debian.org/tracker/source-package/roundcube> for a list if interested.

Support for the 1.5 LTS branch has ended, so presumably it is and will remain vulnerable to some or all of these.

-Valtteri

Rejected reason: This CVE ID has been rejected or withdrawn by its CVE Numbering Authority.

In Roundcube Webmail 1.6.x before 1.6.16 and 1.7.x before 1.7.1, an unsanitized subject field in the draft restored value could lead to stored XSS/HTML/CSS injection on shared mailboxes.

Roundcube Webmail 1.6.x before 1.6.16 and 1.7.x before 1.7 has insufficient HTML sanitization that could lead to Cascading Style Sheets (CSS) injection via an SVG document that has an animate element with the attributeName attribute.

Roundcube Webmail 1.6.x before 1.6.16, and 1.7.x before 1.7.1 allows pre-authentication arbitrary file deletion via redis/memcache session poisoning bypass.

In Roundcube Webmail 1.6.x before 1.6.16 and 1.7.x before 1.7.1, the remote image blocking feature can be bypassed via a crafted CSS var() value in an e-mail message, which may lead to information disclosure or access-control bypass.

In Roundcube Webmail 1.6.x between 1.6.14 and 1.6.16 and 1.7.x before 1.7.1, remote image blocking was not honored for URLs pointing to local/private destinations, which may lead to information disclosure or privilege escalation via a text/html email message.

Roundcube Webmail 1.6.x before 1.6.16 and 1.7.x before 1.7.1 has insecure code evaluation logic in LDAP the autovalues option that could lead to code injection. (Support for code evaluation has been removed in 1.6.16 and 1.7.1.)

Roundcube Webmail 1.6.x between 1.6.14 and 1.6.16,and 1.7.x before 1.7.1 has Insufficient Cascading Style Sheets (CSS) sanitization in HTML e-mail messages may lead to SSRF or Information Disclosure, e.g., if stylesheet links point to local network hosts. The issue stems from an insufficient fix for CVE-2026-35540.

Roundcube Webmail 1.6.x before 1.6.16 and 1.7.x before 1.7.1 has Pre-authentication SQL injection in the virtuserquery plugin via a pregreplace() backslash escape bypass.

Latest version: 1.7.3

Addendum: versions 1.5.15/1.6.15 were released March 29 that correct regressions introduced in 1.5.14/1.6.14 and fix one more cross-site issue:

SVG Animate FUNCIRI Attribute Bypass — Remote Image Loading via fill/filter/stroke, reported by classnzm.

Announcement is at <https://roundcube.net/news/2026/03/29/security-updates-1.7-rc6-1.6.15-1.5.15>. This appears to be CVE-2026-35545.

-Valtteri

Roundcube, a webmail frontend, released versions 1.5.14 and 1.6.14 on March 18 with fixes to a multitude of vulnerabilities. The 1.7 pre-releases are also affected. From the release announcement <https://roundcube.net/news/2026/03/18/security-updates-1.7-rc5-1.6.14-1.5.14>: Fix pre-auth arbitrary file write via unsafe deserialization in redis/memcache session handler, reported by y0us. Fix bug where a password could get changed without providing the old password, reported by flydragon777. Fix IMAP Injection + CSRF bypass in mail search, reported by Martila Security Research Team. Fix remote image blocking bypass via various SVG animate attributes, reported by nullcathedral. Fix remote image blocking bypass via a crafted body background attribute, reported by nullcathedral. Fix fixed position mitigation bypass via use of !important, reported by nullcathedral. Fix XSS issue in a HTML attachment preview, reported by aikidosecurity. Fix SSRF + Information Disclosure via stylesheet links to a local network hosts, reported by Georgios Tsimpidas (aka Frey), Security Researcher at https://i0.rs/.

The file write is apparently CVE-2026-35537. Roundcube still does not provide CVE numbers in their official announcements, interested parties can look them up for the rest for example at the Debian security tracker <https://security-tracker.debian.org/tracker/source-package/roundcube>.

-Valtteri

An issue was discovered in Roundcube Webmail before 1.5.15 and 1.6.15. The remote image blocking feature can be bypassed via SVG content in an e-mail message. This may lead to information disclosure or access-control bypass. This involves the animate element with attributeName=fill/filter/stroke.