Raw vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:NSummary
CVE-2024-42009 is a critical-severity Cross-site Scripting (CWE-79) vulnerability in Roundcube Webmail. Its CVSS base score is 9.3 (Critical).
Operationally, exploitation aligns with the MITRE ATT&CK technique Keylogging (T1056.001); ranked in the top 0.4% of CVEs by exploit likelihood; CISA has added it to the Known Exploited Vulnerabilities catalog.
The strongest mitigations our analysis identified map to SI-10 (Information Input Validation) and SI-15 (Information Output Filtering) — see the control section below for these in your framework.
Deeper analysis AI-assisted summary
Synthesised by an AI model from the NVD description and linked references — a reading aid, not an authoritative source.
CVE-2024-42009 is a cross-site scripting vulnerability affecting Roundcube webmail versions through 1.5.7 and 1.6.x through 1.6.7. It stems from insufficient sanitization in the message_body() function within program/actions/mail/show.php, which processes email content and permits script execution when a specially crafted message is rendered.
An unauthenticated remote attacker can exploit the flaw by sending a malicious email to a victim user. Successful exploitation allows the attacker to hijack the victim's Roundcube session, enabling theft of emails and the ability to send messages from the compromised account with CVSS 9.3 impact reflecting high confidentiality and integrity consequences across affected instances.
Roundcube has released versions 1.5.8 and 1.6.8 to address the issue, as detailed in the project's security announcements and GitHub release notes. The associated EPSS score of 0.9141 indicates substantial exploitation likelihood, and external analysis has highlighted risks to government email systems using the affected software.
OWASP Top 10 for Web (2025)
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2024-39391
Vulnerability Data
A Cross-Site Scripting vulnerability in Roundcube through 1.5.7 and 1.6.x through 1.6.7 allows a remote attacker to steal and send emails of a victim via a crafted e-mail message that abuses a Desanitization issue in message_body() in program/actions/mail/show.php.
- CWE(s)
- KEV Date Added
- 09 June 2025
Related Threats
MITRE ATT&CK Enterprise TechniquesAI
Why these techniques?
XSS vulnerability enables arbitrary JS execution (T1059.007, T1203) in authenticated webmail context when viewing crafted emails, facilitating keylogging (T1056.001), stealing web session cookies/credentials from browsers (T1539, T1555.003), email collection (T1114), and abuse of valid accounts to send emails (T1078).
Likely ATT&CK TechniquesAI
Techniques this vulnerability likely enables, inferred from its description, weakness type, and attributed-actor tradecraft. Confidence is per-technique.
CVEs Like This One
Affected Assets
Mitigating Controls
Control response
Mitigating Controls (NIST 800-53 r5) AI
Directly requires validation and sanitization of untrusted input (email message body) before rendering, which is the exact root cause in message_body().
Requires filtering of information output to users, preventing the desanitized script content from executing in the victim's browser.
Provides mechanisms to detect and block malicious code delivered via email messages before it reaches the rendering function.
Mitigating Controls (NIST CSF 2.0) AI
Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.
Secure SDLC practices directly target introduction of XSS via coding standards/testing (mostly), yet the single broad outcome leaves many specific neutralization vectors unaddressed (partial).
Patching and EOL replacement can remediate known XSS instances in libraries or frameworks (partial) but do nothing to enforce input neutralization in application code (none).
Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI
Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.
Secure-coding testing and automated code-analysis tools are applied to detect improper neutralization of script-related content during web-page generation.
Knowledge exchange on emerging attack techniques and patches reduces the likelihood that cross-site scripting flaws remain unaddressed in deployed applications.
Operational indicators of compromise for web-application attacks can be incorporated into WAF or input-filtering rules, lowering the likelihood that unsanitized data reaches the browser.
Requiring language-specific secure-coding standards and automated scanning during the SDLC catches missing output encoding or improper neutralization of untrusted data before the software reaches production.
Secure-coding standards, SAST scans and removal of insecure code samples together eliminate the failure to neutralize script content that produces cross-site scripting flaws.
Webpage malware scanning and block-listing of known malicious sites reduce the likelihood that reflected or stored script payloads reach a user’s browser.