Bug 2558658 (CVE-2026-114716)

Summary: CVE-2026-114716 roundcubemail: roundcubemail: Mail header injection via unvalidated inline image media type
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
Status: NEW --- QA Contact:
Severity: high Docs Contact:
Priority: high    
Version: unspecifiedKeywords: Security
Target Milestone: ---   
Target Release: ---   
Hardware: All   
OS: Linux   
Whiteboard:
Fixed In Version: Doc Type: ---
Doc Text:
A flaw was found in Roundcube Webmail. The application does not properly validate media type values extracted from inline image data URIs when preparing outgoing messages. A remote authenticated attacker can exploit this vulnerability by submitting specially crafted messages with newline characters in the media type, allowing them to inject arbitrary Multipurpose Internet Mail Extensions (MIME) headers into outgoing emails. This issue can enable an attacker to tamper with message structure, manipulate recipients, or evade security filters.
 Story Points: ---
Clone Of: Environment:
Last Closed: Type: ---
Regression: --- Mount Type: ---
Documentation: --- CRM:
Verified Versions: Category: ---
oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: --- Target Upstream Version:
Embargoed:
Bug Depends On: 2558888, 2558892    
Bug Blocks:    

Description OSIDB Bzimport 2026-10-22 01:43:39 UTC 
Roundcube Webmail before 1.6.20 and 1.7.x before 1.7.5 is affected by a mail header injection vulnerability. rcmail_sendmail::extract_inline_images() used the media type taken from an inline image data URI without validating it, so a remote authenticated attacker could inject arbitrary MIME part headers into the outgoing message by placing CRLF sequences in that media type. Upstream fixed this in the commit “Fix mail header injection via media type in an inline image data URI”, which validates the media type with rcube_mime::is_mimetype_valid().