KEV Intelligence

Vulnerability report

Exploited in the wild Confirmed confidence In CISA KEV

CVE-2023-5631

Stored XSS vulnerability in Roundcube

Roundcube / Roundcubemail · affected before 1.6.3

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Severity
CVSS 6.1 · Medium
Confidence
Confirmed
Exploit status
Exploited in the wild
EPSS
75.9%
First observed
—
Last observed
—

Decision summary

What security teams need to know first

Direct answers before the deeper technical record.

What it is

CVE-2023-5631 is an unauthenticated Stored XSS vulnerability in Roundcube. Roundcube before 1.4.15, 1.5.x before 1.5.5, and 1.6.x before 1.6.4 allows stored XSS via an HTML e-mail message with a crafted SVG document...

Is it exploited?

Yes. KEV Intelligence tracks this CVE as a known exploited vulnerability. Confidence is confirmed.

Who is affected?

Roundcube / Roundcubemail affected before 1.6.3.

What should we do?

Prioritize remediation. Validate affected assets and apply vendor fixes on an accelerated timeline.

Overview

Stored XSS vulnerability in Roundcube

Roundcube before 1.4.15, 1.5.x before 1.5.5, and 1.6.x before 1.6.4 allows stored XSS via an HTML e-mail message with a crafted SVG document because of program/lib/Roundcube/rcube_washtml.php behavior. This could allow a remote attacker

to load arbitrary JavaScript code.

Vendor Product Affected Status
Roundcube Roundcubemail Before 1.6.3 Affected
Roundcube Roundcubemail Before 1.5.4 Affected
Roundcube Roundcubemail Before 1.5.14 Affected
Roundcube Roundcubemail 1.6.4 Unaffected
Roundcube Roundcubemail 1.5.5 Unaffected
Roundcube Roundcubemail 1.5.15 Unaffected
Published
18 Oct 2023
Exploitation Reported
26 Oct 2023
Attack vector
Remote
Complexity
Low
Privileges
None
User interaction
Required

Tags

php cisa java nessus_scanner

CVE References

Exploitation evidence

Why KEV Intelligence marks this CVE as exploited

Third-party attestation and first-party sensor observation are shown separately so teams can judge the evidence chain.

Exploited in the wild

CISA

Recorded 26 Oct 2023

Independent exploitation attestation added to the KEV Intelligence record.

Known exploited vulnerability sources

Per-source evidence links for KEV attestations are available through the KEV Intelligence Pro API.

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Source Added
CISA First 2023-10-26 00:00 UTC

Detection

Operational artifacts and observed signals

Make the evidence actionable in scanner, SOC, and edge-control workflows.

Observed signals

Request targets
0
User-Agents
0

Raw values available in Pro and Enterprise.

Virtual patch status

No KEV Intelligence virtual patch is currently available. Future rules ship for ModSecurity, Cloudflare, and AWS WAF.

Learn about virtual patches →

Scanner Artifacts

Scanner and exploit-framework references linked to this CVE.

Scanner Reference Detected
Nessus https://www.tenable.com/plugins/nessus/114562 02 Jun 2025

Risk and context

Severity, weaknesses, and research context

CVSS v3.1

6.1 Medium
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N

EPSS

75.9%

Weaknesses

Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') CWE-79

Timeline

From disclosure to observed exploitation

  1. Nessus plugin available

    Scanner coverage available

  2. Added to CISA KEV

    Listed in the CISA Known Exploited Vulnerabilities catalog

  3. CVE published

    Vulnerability disclosed publicly

  4. CVE ID reserved

    Identifier reserved by the CNA

Pro API

Automate this intelligence

Confidence, exploit status, sensor telemetry, PoCs, scanner integrations, mentions, and tags are available programmatically for VM, SOC, and CTI workflows.

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  • Evidence confidence and provenance
  • First-party sensor telemetry
  • PoC and scanner references
  • Affected versions and enrichment
  • Automation-ready JSON delivery

GET /api/v2/pro/kevs/CVE-2023-5631

Free JSON includes basic KEV fields 
{
  "cve_id": "CVE-2023-5631",
  "confidence": "Confirmed",
  "cvss_score": 6.1,
  "cvss_estimated": false,
  "epss_score": 0.75873,
  "exploit_status": {
    "exploited_in_the_wild": true,
    "active_exploitation_observed": false
  },
  "sensor_telemetry": { "attempts": 0, "sensors": 0 }
}

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