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Full vulnerability report · 2023
CVE-2023-5631High confidence

Roundcube Webmail Persistent Cross-Site Scripting (XSS) Vulnerability

Roundcube · Webmail

6.1MediumCVSS 3.1
Recommended action
Patch now

CISA confirms exploitation in the wild and lists 2023-11-16 as the remediation due date.

Patch available
R
Operational reassessment

Published severity in operational context

Open reassessment dashboard →
Published severityMediumOperational priority:Critical, raised 2 bands.upgradedsince 26 Oct 2023

Evidence used

  • CISA confirms exploitation in the wild.
  • A structured source references public exploit or proof-of-concept material.
  • EPSS is 75.87% for the current model date.

Compensating controls

  • Validate the affected product branch and deploy the verified fixed release.
  • Restrict the affected network interface to trusted sources where business-safe.
  • Increase monitoring for the attack path and post-exploitation behaviour described in the report.

Verification

  1. Confirm that the asset runs Roundcube Webmail and falls inside the recorded affected range.
  2. Verify the installed build against the product-specific fixed version after deployment.
  3. Validate exposure, authentication requirements and compensating controls in the actual environment.
  4. Reopen this reassessment when CVSS, KEV, EPSS, exploit evidence or remediation changes.
Mitigation target: Within 3 daysRemediation target: Within 90 days

This automated reassessment organises public evidence. It does not know asset exposure, business impact or control effectiveness and does not replace CVSS or a human risk decision.

Distribution package intelligence

Release-specific package status

Debian findings are scoped to the named distribution, release and source package. An absent finding does not mean a package is unaffected.

4 package states
Repository candidate not checked

A published vendor fix does not prove that a matching update is enabled and installable on a particular asset. Confirm the local package candidate before scheduling remediation.

Distribution releaseSource packageVendor stateFixed versionEvidence
Debian trixietrixie · sourceroundcubeVendor fix publishedDebian records a fixed source-package version for this release.1.6.4+dfsg-1Debian Security Tracker ↗Source updated 5 Oct 2026
Debian bookwormbookworm · sourceroundcubeVendor fix publishedDebian records a fixed source-package version for this release.1.6.4+dfsg-1~deb12u1Debian Security Tracker ↗Source updated 5 Oct 2026
Debian forkyforky · sourceroundcubeVendor fix publishedDebian records a fixed source-package version for this release.1.6.4+dfsg-1Debian Security Tracker ↗Source updated 5 Oct 2026
Debian sidsid · sourceroundcubeVendor fix publishedDebian records a fixed source-package version for this release.1.6.4+dfsg-1Debian Security Tracker ↗Source updated 5 Oct 2026
Optional official sources

National CERT insights
?CERT means Computer Emergency Response Team; CSIRT is the closely related term Computer Security Incident Response Team.

Choose official national sources for this report. Each advisory shows its original language. Your selection is remembered on this device and included in shared links.

Official European source

ENISA European Vulnerability Database

Official EUVD identifiers, advisory evidence and known-exploited context. Missing fields are not treated as evidence of low risk.

1 current
ENISA EUVD identifier

EUVD-2023-57924

CISA KEV mirrored by ENISA

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.

EUVD state
Present in the current official mapping
Known exploitation
Recorded by ENISA since 26 Oct 2023. Evidence sources: cisa_kev.
ENISA score
6.1 · CVSS 3.1
Advisory evidence
3 linked advisory records
Explicit mitigation evidence

Only statements that explicitly mention a fix, patch, update, workaround or mitigation are shown here.

  • csaf_opensuse · openSUSE-SU-2023:0345-1Security update for roundcubemail
Recommended actionPatch now

CISA confirms exploitation in the wild and lists 2023-11-16 as the remediation due date.

Patch available
01

What, why and how

Roundcube Webmail contains a persistent cross-site scripting (XSS) vulnerability that allows a remote attacker to run malicious JavaScript code.

What

Roundcube Webmail contains a persistent cross-site scripting (XSS) vulnerability that allows a remote attacker to run malicious JavaScript code.

Why

Attacker-controlled content can reach a browser as executable script without sufficient output encoding or sanitisation.

How

An attacker operating through a network path may attempt exploitation without authentication after a user interaction. If successful, the issue may cause the confidentiality, integrity or availability impact described by the vendor.

What

Roundcube Webmail contains a persistent cross-site scripting (XSS) vulnerability that allows a remote attacker to run malicious JavaScript code.

Why

Attacker-controlled content can reach a browser as executable script without sufficient output encoding or sanitisation.

How

An attacker operating through a network path may attempt exploitation without authentication after a user interaction. If successful, the issue may cause the confidentiality, integrity or availability impact described by the vendor.

02

Exploit reality and attack path

CVSS severity, EPSS forecast probability, public exploit material and CISA-confirmed exploitation are separate signals.

Observed exploitation
?Confirmed exploitation and public exploit material are separate signals. Attacks can occur without public proof-of-concept or exploit code.
Confirmed in the wild

CISA added this CVE to its Known Exploited Vulnerabilities catalogue on 2023-10-26.

Public PoC / exploit material
?Confirmed exploitation and public exploit material are separate signals. Attacks can occur without public proof-of-concept or exploit code.
Reference recorded

A structured CVE source labels at least one public reference as exploit material. BlackTree has not independently validated that it is safe, reliable or weaponised.

Likely attack path
a network path → Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') → cause the confidentiality, integrity or availability impact described by the vendor
Attack surface
Network
Privileges required
None: unauthenticated exploitation is possible
User interaction
Required interaction required
Attack complexity
Low: no specialised conditions are recorded
Security boundary
Changed: exploitation can affect a different security authority
Weakness
?CWE means Common Weakness Enumeration: a standard category for the underlying weakness.
CWE-79 ↗

CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting'). The product does not neutralize or incorrectly neutralizes user-controllable input before it is placed in output that is used as a web page that is served to other users.

CVSS vector
?CVSS means Common Vulnerability Scoring System. The vector records the metric values used to calculate technical severity.
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N

Common Vulnerability Scoring System 3.1: the compact vector below is decoded into plain language.

AVNetworkAttack vector: The vulnerable component can be reached over a network.ACLowAttack complexity: No specialised conditions are required beyond attacker-controlled input.PRNonePrivileges required: The attacker does not need an account or existing privileges.UIRequiredUser interaction: Another user must perform an action for exploitation to succeed.SChangedScope: The attack can affect a component governed by a different security authority.CLowConfidentiality impact: A successful attack can cause a limited loss.ILowIntegrity impact: A successful attack can cause a limited loss.ANoneAvailability impact: No direct loss is represented by this metric.
Post-exploitation / living off the land
No specific living-off-the-land technique is confirmed in the structured sources. Monitor normal administration tools for activity inconsistent with the affected service's baseline.
NetworkUnauthenticatedCWE-79CISA KEVPublic exploit reference
A

Official authority intelligence

Only matched European and national findings are included. Language selectors and unavailable sources are omitted.

ENISA EUVD · EUVD-2023-57924Known-exploited evidence recorded

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.

Official EUVD record ↗
BSI · German · WID-SEC-2023-2657Roundcube: Schwachstelle ermöglicht Cross-Site Scripting

Ein entfernter, anonymer Angreifer kann eine Schwachstelle in Roundcube ausnutzen, um einen Cross-Site Scripting Angriff durchzuführen.

Official advisory ↗
Cyber Security Agency of Singapore · English · CSA-SB-20231025Security Bulletin 25 Oct 2023

The Cyber Security Agency of Singapore included this CVE in its official Security Bulletin 25 Oct 2023, published on 25 October 2023. Open the linked bulletin for the product, severity and reference information published in that issue.

Official advisory ↗
CERT-FR · French · CERTFR-2023-AVI-0893Vulnérabilité dans Roundcube Webmail

Une vulnérabilité a été découverte dans Roundcube Webmail. Elle permet à un attaquant de provoquer une injection de code indirecte à distance (XSS).

Official advisory ↗
JVN iPedia · Japanese · JVNDB-2023-015120Roundcube.net の Webmail 等複数ベンダの製品におけるクロスサイトスクリプティングの脆弱性

Roundcube.net の Webmail 等複数ベンダの製品には、クロスサイトスクリプティングの脆弱性が存在します。

Official advisory ↗
KISA KrCERT/CC · Korean · KNVD-6024현재 악용되고 있는 Exploit(Update. 2023-10-26)

Roundcube Webmail contains a persistent cross-site scripting (XSS) vulnerability that allows a remote attacker to run malicious JavaScript code.

Official advisory ↗
03

Patch and workaround

Operational remediation based on structured source evidence.

Status
?Patch availability is based on structured fixed-version fields and authoritative update references. If no fix is verified, check the vendor advisory before making a change.
Patch available
Affected
Roundcubemail: 1.6.0 < 1.6.3, 1.4.0 < 1.5.14, 1.5.0 < 1.5.4
Fixed
Roundcubemail: 1.6.4, 1.5.5, 1.5.15
Action
Review the linked authoritative reference and apply the recorded fixed release appropriate to the affected product branch.
Workaround
No verified workaround is recorded. If business-safe, reduce exposure to the affected interface and allow only trusted sources until authoritative guidance is available.
04

Evidence and provenance

Published 18 Oct 2023 · Last source change 21 Oct 2025, 23:05 UTC · CWE-79 · Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')

CVE recordCVE.org · 5.1
CVSS sourceCNA
EPSS source
?The date BlackTree first stored a score for this CVE from the daily FIRST EPSS feed.
FIRST · tracked since 2026-08-14
European sourceENISA EUVD · EUVD-2023-57924
Product sourceCISA KEV
Remediation sourceCVE/CNA references
CWE sourceCNA
NVD statusNVD enriched

Core structured fields are present and their contributing authorities are shown above.

Material change intelligence

What changed after publication

View recent updates ↗
  1. Affected versionsThe structured affected or fixed version information changed.
    Before
    1.6.0 < 1.6.3; 1.5.0 < 1.5.4; 1.4.0 < 1.5.14 · Fixed: 1.6.4; 1.5.5; 1.5.15
    After
    Roundcubemail: 1.6.0 < 1.6.3, 1.5.0 < 1.5.4, 1.4.0 < 1.5.14 · Fixed: Roundcubemail: 1.6.4, 1.5.5, 1.5.15
    CNA ↗
Material fields only · duplicate refreshes suppressed · history retained for the configured operational retention period
CVE published
Added to CISA KEV
Fixed release or patch reference recorded
ENISA EUVD · EUVD-2023-57924↗CISA KEV record↗CVE authority or vendor reference↗Patch or update reference↗Patch or update reference↗Public exploit reference↗Official CVE record (CNA and ADP data)↗NVD record↗
Technical terms and abbreviations used in this report
CVE
Common Vulnerabilities and Exposures: the public identifier for one disclosed vulnerability.
CVSS
Common Vulnerability Scoring System: a technical severity framework; it is not patching priority by itself.
EPSS
Exploit Prediction Scoring System: FIRST's estimate of the probability that exploitation activity will be observed in the next 30 days; it is a forecast, not confirmation.
CWE
Common Weakness Enumeration: the standard category describing the underlying software or hardware weakness.
CNA
CVE Numbering Authority: an organisation authorised to assign and publish CVE records.
CISA ADP
Cybersecurity and Infrastructure Security Agency Authorized Data Publisher: structured enrichment added to a CVE record.
NVD
National Vulnerability Database: NIST's enrichment service for CVE records.
CERT / CSIRT
A computer security incident response team that publishes warnings or coordinates incident response.
PoC
Proof of concept: public material that demonstrates or helps reproduce exploitation.
CSAF
Common Security Advisory Framework: a machine-readable format for security advisories.
LoTL
Living off the land: abuse of legitimate tools or system functions during an attack.
Free version - for non-commercial use only.CVE-2023-5631 · cve.blacktree.nl