CVE-2026-114728
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AI Threat Summary
CVE-2026-114728 is a moderate vulnerability with a CVSS score of 5.3 affecting the target software. Threat hunters should monitor for exploit attempts and apply vendor patches immediately.
Description
Roundcube Webmail before 1.6.20 and 1.7.x before 1.7.5 is affected by a remote content blocking bypass in the handling of FuncIRI attributes. rcube_washtml detected the CSS url() token with a pattern that enumerated only some of its escaped spellings, so values using other CSS escape sequences, for example \000075rl( or u\72 l(, were not recognized and remote content was loaded from an HTML message without the user's consent. Upstream fixed this in the commit “Fix remote content blocking bypass via CSS escapes in FuncIRI attributes (again)”, which resolves CSS escapes before matching and also inspects the `to`, `from` and `by` attributes.
Attack Chain
Attacker scans for vulnerable versions using version banners or PoC scanners
Attacker triggers CVE-2026-114728 vulnerability with a crafted request or payload
Vulnerability exploited to perform unauthorized actions on the target system
Depending on vulnerability type, attacker achieves data access, service disruption, or code execution
MITRE ATT&CK Techniques
Indicators of Compromise
| Type | Value | Description | |
|---|---|---|---|
| user_agent | Mozilla/5.0 (compatible; exploit/1.0) |
Generic exploit scanner user agent pattern | |
| url | /api/vuln-endpoint?payload=<malicious> |
Exploit attempt against application endpoint — monitor access logs for anomalous params |
Remediation
Quick Facts
| CVE ID | CVE-2026-114728 |
| CVSS Score | 5.3 |
| Vector | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N |
| Published | 2026-10-22 |
| Exploited | No |
| CISA KEV | No |
| PoC | Not public |
References
- https://bugs.debian.org/1151279
- https://github.com/roundcube/roundcubemail/commit/2f74267f0e…
- https://github.com/roundcube/roundcubemail/commit/ff4fcfdd29…
- https://github.com/roundcube/roundcubemail/releases/tag/1.6.…
- https://github.com/roundcube/roundcubemail/releases/tag/1.7.…
- https://roundcube.net/news/2026/10/19/security-updates-1.6.2…