CVE-2024-37383
RoundCube Webmail Cross-Site Scripting (XSS) Vulnerability
Description
CVE-2024-37383 is a medium-severity cross-site scripting (XSS) vulnerability in Roundcube Webmail affecting versions before 1.5.7 and 1.6.x before 1.6.7. Rated 6.1 on the CVSS v3.1 scale, the vulnerability allows an attacker to inject malicious scripts through SVG animate attributes in email messages, which execute in the context of the victim's browser session when the email is viewed. With an EPSS score of 0.66827 (98.5th percentile) and inclusion in CISA's Known Exploited Vulnerabilities catalog with a remediation deadline of November 14, 2024, this vulnerability poses a significant threat to organizations relying on Roundcube for webmail access.
KEV Information
CVSS Score
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:NOpen in CalculatorAffected Products
| Vendor | Product | Version |
|---|---|---|
| roundcube | webmail | < 1.5.7; >= 1.6.0, < 1.6.7 |
| debian | debian linux | 10.0 |
Multiple CVSS Assessments
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
References
- https://github.com/roundcube/roundcubemail/commit/43aaaa528646877789ec028d87924ba1accf5242(Patch)
- https://github.com/roundcube/roundcubemail/releases/tag/1.5.7(Release Notes)
- https://github.com/roundcube/roundcubemail/releases/tag/1.6.7(Release Notes)
- https://lists.debian.org/debian-lts-announce/2024/06/msg00008.html(Mailing List, Third Party Advisory)
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2024-37383(US Government Resource)
Weakness Type
The specific CWE classifications for CVE-2024-37383 have not been formally assigned. The vulnerability is a stored cross-site scripting (XSS) weakness in Roundcube Webmail's email rendering engine. Roundcube's HTML sanitizer, which is responsible for stripping dangerous content from incoming emails before rendering them in the browser, fails to properly handle SVG animate element attributes. SVG animations can contain JavaScript references through attributes like "values," "from," "to," and "begin" that execute code when the animation triggers. By crafting an email with malicious SVG animate attributes, an attacker can inject JavaScript that bypasses the sanitizer and executes in the victim's browser session when the email is opened.
Impact Analysis
The CVSS vector (AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N) indicates that CVE-2024-37383 is remotely exploitable with low complexity, requires no authentication, but needs user interaction (opening the malicious email). The Scope Changed designation means the XSS payload executes in the context of the victim's browser session, potentially affecting resources beyond the Roundcube application itself. Confidentiality (Low) and Integrity (Low) reflect the ability to steal session cookies, read email content, and modify the displayed page content. While the per-metric impact is rated Low, the business consequences can be severe: an attacker can steal Roundcube session tokens to hijack email accounts, read all emails in the victim's inbox, send emails on the victim's behalf, exfiltrate sensitive communications, and potentially chain the XSS with other attacks against internal applications accessible from the victim's browser. The EPSS score of 0.66827 (98.5th percentile) reflects high exploitation probability. Roundcube is widely deployed by ISPs, universities, and organizations as their primary webmail solution, making it an attractive target for espionage campaigns, phishing operations, and credential theft.
Exploit Maturity
CVE-2024-37383 is confirmed as actively exploited in the wild and has been added to CISA's Known Exploited Vulnerabilities catalog with a remediation deadline of November 14, 2024. The ransomware association is classified as "Unknown." The EPSS score of 0.66827 (98.5th percentile) confirms very high exploitation probability. The patch commit is publicly available on GitHub, making the vulnerability details and the exact fix transparent to potential attackers. Fixed versions 1.5.7 and 1.6.7 have been released. Roundcube XSS vulnerabilities have historically been exploited by sophisticated threat actors including nation-state groups for targeted email surveillance campaigns, making this vulnerability particularly concerning for organizations handling sensitive communications.
Remediation
- Update Roundcube Webmail immediately — Upgrade to version 1.5.7 or 1.6.7 depending on your release branch. The fix is contained in commit 43aaaa5.
- Implement Content Security Policy (CSP) headers — Configure strict CSP headers on your Roundcube installation to mitigate the impact of any XSS vulnerabilities by restricting inline script execution and limiting the domains from which scripts can be loaded.
- Review email server logs for suspicious messages — Examine mail server logs for emails containing SVG elements with animate tags, particularly those with unusual attribute values. These may indicate attempted or successful exploitation of this vulnerability.
- Invalidate active sessions — After applying the update, invalidate all active Roundcube sessions to terminate any sessions that may have been compromised through XSS exploitation. This forces all users to re-authenticate with fresh session tokens.
- Deploy a web application firewall (WAF) — Configure WAF rules to detect and block emails containing potentially malicious SVG animate attributes as an additional defense layer for the patching window and against future SVG-based attack variants.
Technical Details
The CVSS v3.1 vector for CVE-2024-37383 is CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N, resulting in a base score of 6.1 (Medium). Attack Vector (Network) confirms exploitation via email delivery over the network. Attack Complexity (Low) means crafting the malicious email is straightforward. Privileges Required (None) indicates any external attacker can send the malicious email — no Roundcube account is needed. User Interaction (Required) means the victim must open or preview the email in Roundcube. Scope (Changed) is significant — the XSS executes in the victim's browser context, potentially accessing cookies, localStorage, and other origin-scoped data beyond Roundcube itself. Confidentiality and Integrity (both Low) reflect the typical XSS impact of reading and modifying page content, though the real-world consequences depend on what the attacker's payload targets. The attack mechanism exploits a gap in Roundcube's HTML sanitizer. When rendering email content, Roundcube strips dangerous HTML elements and attributes to prevent script execution. However, SVG animate element attributes (such as "values," "begin," "from," and "to") were not included in the sanitizer's blocklist. An attacker can embed an SVG element with animate tags that reference JavaScript through these attributes, causing the browser to execute the injected code when rendering the animation.
Frequently Asked Questions
What is CVE-2024-37383?
CVE-2024-37383 is a cross-site scripting (XSS) vulnerability in Roundcube Webmail that allows attackers to execute malicious JavaScript in a victim's browser by sending a specially crafted email containing SVG animate attributes. It affects Roundcube versions before 1.5.7 and 1.6.x before 1.6.7.
How is CVE-2024-37383 exploited?
An attacker sends a specially crafted email to the target. The email contains SVG elements with animate attributes that embed JavaScript code. When the victim opens or previews the email in Roundcube, the XSS payload executes in their browser session, potentially stealing session cookies or email content.
Is CVE-2024-37383 being used in real attacks?
Yes, CISA has confirmed active exploitation and added this vulnerability to its KEV catalog. Roundcube XSS vulnerabilities have historically been targets for sophisticated threat actors, including nation-state groups conducting email surveillance campaigns.
How do I fix CVE-2024-37383?
Update Roundcube Webmail to version 1.5.7 (for the 1.5.x branch) or 1.6.7 (for the 1.6.x branch). After updating, invalidate all active sessions and implement Content Security Policy headers to mitigate future XSS risks.
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