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Actively exploited in the wild. This CVE is on the CISA Known Exploited Vulnerabilities list — treat remediation as urgent. Federal remediation due by 16 Nov 2023.
Debian LinuxOperating system · Debian

CVE-2023-5631

MEDIUM · 5.4 CVSS v3.1 Published 2023-10-18
Fix available
A fix is available. Upgrade to 1.4.15 / 1.5.5 or later.
See remediation →
98/100
Remediation priority · Urgent
In the wild High EPSS Public exploit Remotely reachable Patch available

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
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.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · high confidence

Stored XSS vulnerability in Roundcube's HTML email processing (rcube_washtml.php). Attackers can embed malicious JavaScript within SVG documents inside HTML emails; when recipients view these emails, arbitrary JavaScript executes in their browser session.

MitigationUpdate Roundcube to version 1.4.15, 1.5.5, or 1.6.4 or later. Consider disabling HTML email rendering or deploying a mail security gateway as additional layers of defense.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
Debian LinuxOperating system
Affected:= 10.0= 11.0= 12.0
FedoraOperating system
Affected:= 39
WebmailApplication
Affected:< 1.4.15>= 1.5.0, < 1.5.5>= 1.6.0, < 1.6.4

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Network
Complexity
Low
Privileges
Low
User interaction
Required
Scope
Changed
Confidentiality
Low
Integrity
Low
Availability
None

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

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Identify installed Roundcube version
    Locate the Roundcube version file (typically VERSION in the web root or via composer.json) or check the version displayed in the Roundcube login footer
    Affected if The version is < 1.4.15, OR >= 1.5.0 and < 1.5.5, OR >= 1.6.0 and < 1.6.4
  2. Verify HTML email rendering is enabled
    In Roundcube settings, check Preferences > Mail Viewing > Display HTML messages. Alternatively, check the Roundcube config file (config/defaults.inc.php or config.inc.php) for the 'preview_html' or 'htmlemail' setting
    Affected if HTML email rendering is set to on or allowed (the XSS triggers only when viewing HTML emails)
  3. Confirm the washtml.php sanitization component exists
    Locate the rcube_washtml.php file in the Roundcube program/include or program/lib directory
    Affected if The file exists (the vulnerability resides in this specific sanitization component)

You are affected if your Roundcube version falls within the vulnerable ranges AND HTML email rendering is enabled, allowing crafted SVG content in HTML emails to execute JavaScript when viewed.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Upgrade available Upgrade to 1.4.15 / 1.5.5 / 1.6.4 or later
Fixed in 1.4.151.5.51.6.4
Vendor patch bugs.debian.org →
Interim mitigation

Update Roundcube to version 1.4.15, 1.5.5, or 1.6.4 or later. Consider disabling HTML email rendering or deploying a mail security gateway as additional layers of defense.

Recommended fix High confidence

Upgrade to Roundcube 1.4.15, 1.5.5, or 1.6.4 (or later releases in those branches)

  1. Identify currently installed Roundcube version by checking the version file or webmail interface
  2. Download the appropriate fixed version of Roundcube (1.4.15, 1.5.5, or 1.6.4 or later) from the official Roundcube repository at github.com/roundcube/roundcubemail
  3. Backup the existing Roundcube installation and database before upgrading
  4. Extract the new version and replace the existing files, preserving local configuration in config/ directory
  5. Run database migration scripts if included in the upgrade (check the UPGRADING file in the distribution)
  6. Clear any cached templates and sessions to ensure new code is loaded
  7. Verify the upgrade was successful by logging in and checking the version displayed
Caveat Upgrades within the same minor version branch should be safe; always backup before upgrading

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Debian Linux Exploited in the wild — priority engagement
  • Consultation2.0 h
  • Implementation4.0 h
  • Testing4.0 h
  • Review / QA2.0 h
12.0 hours of engineering $2,080
Get it fixed fast

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $3,328.

Scan for this in your stack

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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2023-5631 in production — separate from our analysis above.

No notes yet

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
  • No weaponised exploit code, or anything meant to cause harm
  • No spam, self-promotion, credentials, or personal data