CVE-2026-114716: CWE-99 Improper Control of Resource Identifiers ('Resource Injection') in Roundcube Webmail
Description
CVE-2026-114716 is a mail header injection vulnerability in Roundcube Webmail versions 1.6.0 up to but not including 1.6.20, and 1.7.0 up to but not including 1.7.5. The flaw exists in the rcmail_sendmail::extract_inline_images() function, which uses the media type from an inline image data URI without proper validation. This allows a remote authenticated attacker to inject arbitrary MIME part headers into outgoing messages by inserting CRLF sequences in the media type. The issue has been fixed by validating the media type with rcube_mime::is_mimetype_valid().
CVSS v3.1
Score 8.5high
Affected software
Roundcube
Webmail
pkg:github/WebmailRun on your own infrastructure? Check whether these packages are installed with threat-finder — our free open-source scanner.
Weaknesses
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
Roundcube Webmail before versions 1.6.20 and 1.7.5 is vulnerable to a mail header injection due to improper validation of the media type in inline image data URIs. The function rcmail_sendmail::extract_inline_images() accepts media types without checking for malicious CRLF sequences, enabling an authenticated attacker to inject arbitrary MIME headers into outgoing emails. The vulnerability is addressed by validating the media type using rcube_mime::is_mimetype_valid(), preventing injection of malicious headers.
Potential Impact
An authenticated attacker can inject arbitrary MIME part headers into outgoing email messages, potentially allowing manipulation of email content or headers. This can lead to message integrity issues and may facilitate further attacks relying on crafted email headers. The CVSS 3.1 score is 8.5 (high severity), indicating a significant impact on confidentiality and integrity, with no impact on availability.
Mitigation Recommendations
A fix is available and has been implemented upstream by validating the media type in inline image data URIs with rcube_mime::is_mimetype_valid(). Users should upgrade Roundcube Webmail to version 1.6.20 or later, or 1.7.5 or later, to remediate this vulnerability.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- mitre
- Date Reserved
- 2026-10-22T01:17:44.860Z
- Cvss Version
- 3.1
- State
- PUBLISHED
Threat ID: 6ad967fa4d27ba8daa1a2823
Added to database: 10/22/2026, 01:33:46 UTC
Last enriched: 10/22/2026, 01:45:20 UTC
Last updated: 10/22/2026, 01:48:31 UTC
Views: 2
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