Roundcube's HTML sanitization path for message rendering allows loopback, localhost, RFC1918, link-local, and ULA URLs even when remote content loading is disabled. A remote attacker can send an HTML email that causes the victim's browser to issue requests to local or private-network services simply by opening the message preview.
This CVE has been withdrawn by MITRE
MITRE marked CVE-2026-9818 as REJECTED on . It is no longer considered a valid vulnerability record. The original content below is preserved for historical reference only.
Reason given by MITRE
This CVE ID has been rejected or withdrawn by its CVE Numbering Authority.
CVE-2026-9818
✕ Withdrawn — historical dataMEDIUMPre-NVD 4.7
4.7CVSS
- CVSS v3
- 4.7
- EchelonGraph score
- Not yet assessedThis CVE record was withdrawn by its numbering authority, so there is no vulnerability to rate.
- EPSS PROB
- —
- EPSS %ILE
- —
- KEV
- —Not applicable: this CVE ID was withdrawn
Published
May 28, 2026
Last Modified
May 28, 2026
References (5)
- https://github.com/roundcube/roundcubemail/releases/tag/1.7.1
- https://github.com/roundcube/roundcubemail/releases/tag/1.6.16
- https://github.com/roundcube/roundcubemail/commit/faf867432f51ebbe100382a70a9e3c042415ee1b
- https://github.com/roundcube/roundcubemail/commit/7b52353653a67e6073b97d70eb94047132b78556
- https://advisories.orangecyberdefense.com/advisories/163
Frequently asked(4)
What is CVE-2026-9818?
CVE-2026-9818 is a rejected CVE ID: its record was withdrawn on May 28, 2026 and no longer describes a vulnerability. Reason given: This CVE ID has been rejected or withdrawn by its CVE Numbering Authority.
When was the CVE record for CVE-2026-9818 published?
The CVE record for CVE-2026-9818 was published on May 28, 2026. EchelonGraph's copy of the record carries a last-modified date of May 28, 2026; the record at its source may have been updated since.
What is the CVSS score of CVE-2026-9818?
CVE-2026-9818 has a CVSS base score of 4.7 (the CNA's own assessment, by ocd; NVD's own analysis pending).
How do I remediate CVE-2026-9818?
There is nothing to remediate under CVE-2026-9818: it is a rejected (withdrawn) CVE ID and no longer describes a vulnerability.