How severe is CVE-2024-42009?

CVE-2024-42009 has a CVSS score of 9.3/10, rated CRITICAL. Immediate patching is strongly recommended.

Which packages are affected by CVE-2024-42009?

Affected package information for CVE-2024-42009 is not yet fully mapped. Check the official advisory links for details.

How do I fix CVE-2024-42009?

No fixed version has been published for CVE-2024-42009 yet. Monitor the advisory for updates, apply mitigations recommended by the vendor, and use O3 Security to track when a fix becomes available in your stack.

Is CVE-2024-42009 actively exploited in the wild?

Yes. There are 2 known exploit references for CVE-2024-42009, including . All exploit code should only be run in an isolated sandbox environment for research or authorized testing — never against production systems without explicit written authorization.

What is the EPSS score for CVE-2024-42009?

CVE-2024-42009 has an EPSS (Exploit Prediction Scoring System) score of 91.4%, placing it in the 100th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. A score above 50% indicates significantly elevated exploitation risk — immediate patching is strongly recommended.

Is CVE-2024-42009 in the CISA Known Exploited Vulnerabilities catalog?

Yes. CVE-2024-42009 (RoundCube Webmail Cross-Site Scripting Vulnerability) was added to CISA's Known Exploited Vulnerabilities (KEV) catalog on 2025-06-09. CISA required all US federal civilian agencies to remediate this vulnerability by 2025-06-30. The required action was: Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable. Being listed in the KEV catalog is the strongest possible confirmation of active exploitation — treat this as a critical priority.

Is there exploit tooling available for CVE-2024-42009?

A Nuclei detection template exists for CVE-2024-42009, meaning automated scanners can fingerprint it. Public exploit tooling significantly increases real-world risk — prioritize patching and ensure detection coverage. Exploit tooling should only ever be used in isolated, authorized testing environments.

When was CVE-2024-42009 published, and has it been updated?

CVE-2024-42009 was published on August 5, 2024 and was last updated on April 16, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

CISA KEV·Added 2025-06-09 — agencies required to remediate by 2025-06-30

CVE-2024-42009

CRITICAL

Published

Aug 5, 2024

Updated

Apr 16, 2026

Affected

0 pkgs

Patched

None yet

Exploits

2 known

EPSS Exploitation Probability

via FIRST.org ↗

91.4%probability of exploitation in next 30 days

Very High Risk100th percentile+0.93%

EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.

Description

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.

Exploits & PoCs

Research use only. For defensive security, authorized penetration testing, and academic research only. Never execute exploit code against systems without explicit written authorization.

DaniTheHack3r/CVE-2024-42009-PoC

CVE-2024-42009 Proof of Concept

⭐ 7🍴 1Nov 2025

0xbassiouny1337/CVE-2024-42009

This script exploits a stored XSS vulnerability (CVE-2024-42009) in Roun

⭐ 4🍴 0Jan 2026

Frequently Asked Questions

O3 Security · Impact-Aware SCA

Is CVE-2024-42009 in your stack?

O3 detects CVE-2024-42009 across dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.

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