Vulnerability

CVE-2024-42009

Critical· 9.3KEVCVSS9.3EPSS91%

.rules3/5

RoundCube Webmail Cross-Site Scripting Vulnerability

RoundCube Webmail contains a cross-site scripting vulnerability. This vulnerability could allow 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.

Threat signal

100/100

Severe

Severity

critical

CVSS

9.3

EPSS

91%

Active

KEV

CISA KEV — actively exploited

348d overdue

AffectedRoundcube — Webmail

Added to KEV

2025-06-09

Federal patch due (BOD 22-01)

2025-06-30

Required action (CISA verbatim)

Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.

Vendor advisory + references

CISA description: “RoundCube Webmail contains a cross-site scripting vulnerability. This vulnerability could allow 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.”

CVSS

v3.1Open in FIRST calculator →

9.3/ 10CRITICALCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:N

Attack VectorNetworkExploitable remotely over the internet — no local access needed.
Attack ComplexityLowNo special conditions — exploit works reliably.
Privileges RequiredNoneUnauthenticated — no credentials needed.
User InteractionRequiredRequires user action (click, file open, etc).
ScopeChangedImpact extends beyond the vulnerable component (e.g. sandbox escape).
Confidentiality ImpactHighTotal disclosure of sensitive data.
Integrity ImpactHighTotal compromise of integrity — full data modification possible.
Availability ImpactNoneNo availability impact.

EPSS

Exploit prediction · 30-day horizonFIRST.org →

91.4%

probability of exploitation in next 30 days

p100

higher than 100% of all CVEs

3-day trend↑ 0pp

Statistically about to be weaponized — top-tier triage urgency.

Vendor VEX

No VEX statements published for CVE-2024-42009. Vendors publish VEX (Vulnerability Exploitability eXchange) to assert per-product whether a CVE is actually exploitable in their distribution.

SSVCAct

Active exploitation with total impact on essential/support systems

exploitation: active
automatable: yes
impact: total
mission: support

Lifecycle

2025-06-09Added to CISA KEVransomware: Unknown
2025-06-09Published
2025-06-30Federal patch due (BOD 22-01)
2026-06-12Last modified1 source

No source-event history recorded yet. New revisions will appear here as ingestors re-fetch this CVE.