Server-side request forgery filter bypass in Roundcube Webmail
Key facts
- Attack vector
- Network
- Privileges required
- None
- User interaction
- None
- Attack complexity
- Low
- Impact type
- —
- Confidentiality · integrity · availability
- Low · Low · None
- Fix status
- Fixed
Attack profile from CVSS 3.1 · CNA. Fix status from CNA.
Summary
Roundcube Webmail from 1.6.14 before 1.6.20 and from 1.7.0 before 1.7.5 is affected. The network blocklist in rcube_utils::is_local_url() omits the NAT64 prefixes 64:ff9b::/96 and 64:ff9b:1::/48 and the unspecified address ::/128, so crafted URLs bypass the filter. A remote attacker without privileges can make the server request loopback, link-local and cloud metadata addresses (CWE-918).
Written with Claude Haiku 5.5 from the sources below · 2026-11-04
Description from the CNA
Roundcube Webmail 1.6.14 before 1.6.20 and 1.7.0 before 1.7.5 is affected by a server-side request forgery filter bypass. The network blocklist used by rcube_utils::is_local_url() omitted the RFC 6052 NAT64 prefix 64:ff9b::/96, the RFC 8215 local-use NAT64 prefix 64:ff9b:1::/48 and the unspecified address ::/128, so URLs such as http://[64:ff9b::7f00:1]/ passed the filter and reached loopback, link-local and cloud metadata addresses. Upstream fixed this in the commit “Fix SSRF filter (is_local_url()) bypass via NAT64 64:ff9b::/96”.
Why it matters now
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- None
- Automatable
- Yes
- Technical impact
- Partial
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
Remediation
Upgrade to Roundcube Webmail 1.6.20 or 1.7.5, the fixed release in each affected range. Upstream fixed this in the commit "Fix SSRF filter (is_local_url()) bypass via NAT64 64:ff9b::/96".
Written with Claude Haiku 5.5 from the sources below · 2026-11-04
- Fix · CNA Webmail (Roundcube) Fixed in 1.6.20, 1.7.5
Fixed in the same release
Records fixed by the same vendor advisory or release, as the CNA lists them.
- Advisory ·
Roundcube Webmail — roundcube.net/news/2026/10/19/security-updates-1.6.20-and-1…
20 records Highest priority Priority LOW 20 LOW
Other records, highest priority first
- TI-2026-79177 Roundcube Webmail passes unsafe SVG and EPS content to ImageMagickPriority LOW 38
- TI-2026-79182 Improper authentication in Roundcube Webmail multi-host alias loginsPriority LOW 37
- TI-2026-79174 Object injection in Roundcube Webmail session handlingPriority LOW 37
Vendor assessments
Timeline
- 2026-10-22 Threatist record created from CVE-2026-114730
- 2026-10-22 Alias added: GHSA-8f6h-w7cq-8q8h
- 2026-10-23 Affected versions changed · Red Hat
- 2026-10-23 CVSS score added · Red Hat
- 2026-10-23 Priority changed: MEDIUM → LOW
- 2026-10-28 CISA SSVC decision points changed
References
Patch 4
- https://github.com/roundcube/roundcubemail/commit/6e1d480e730a45f29829b6a11af608d5d6eb3db6
- https://github.com/roundcube/roundcubemail/releases/tag/1.7.5
- https://github.com/roundcube/roundcubemail/releases/tag/1.6.20
- https://github.com/roundcube/roundcubemail/commit/3c3a65f66b53b7aaf3d720acd06e0b102eceb090
More Roundcube Webmail vulnerabilities
- TI-2025-31204 Deserialization of untrusted data in Roundcube Webmail KEVCVSS 3.1CRITICAL 9.9
- TI-2021-19778 Roundcube before 1.3.17 and 1.4.x before 1.4.12 is prone to a potential SQL injection via search or search_params. KEVCVSS 3.1CRITICAL 9.8
- TI-2020-10051 rcube_image.php in Roundcube Webmail before 1.4.4 allows attackers to execute arbitrary… KEVCVSS 3.1CRITICAL 9.8
- TI-2024-28025 A Cross-Site Scripting vulnerability in Roundcube through 1.5.7 and 1.6.x through 1.6.7… KEVCVSS 3.1CRITICAL 9.3
- TI-2017-12250 Roundcube Webmail before 1.1.10, 1.2.x before 1.2.7, and 1.3.x before 1.3.3 allows… KEVCVSS 3.1HIGH 7.8
- TI-2025-41994 Cross-site scripting in Roundcube Webmail KEVCVSS 3.1HIGH 7.2
Sources
- CVE-2026-114730 · CVE Program
- CVE-2026-114730 · NVD
- FIRST EPSS
- GHSA-8f6h-w7cq-8q8h · GitHub Advisory Database · CC BY 4.0
- CVE-2026-114730 · Red Hat security data · CC BY 4.0
This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences