MEDIUM
CVE-2026-35540
CWE-669Published: April 3, 2026· Updated: Apr 7, 2026
6.5
CVSS v3.1
EPSS:0.03%probability of exploitation in 30 daysPercentile:8.8th
Official Description
An issue was discovered in Roundcube Webmail 1.6.0 before 1.6.14. Insufficient Cascading Style Sheets (CSS) sanitization in HTML e-mail messages may lead to SSRF or Information Disclosure, e.g., if stylesheet links point to local network hosts.
Technical Analysis
CVE-2026-35540 can be exploited remotely over the network without requiring physical or adjacent access, significantly expanding the attack surface for threat actors.
The vulnerability requires no privileges and no user interaction, making it a prime target for automated exploitation campaigns and worm-like propagation.
CVSS v3.1 Vector Breakdown
Exploitability
Attack VectorNetwork
Attack ComplexityLow
Privileges Req.None
User InteractionNone
ScopeUnchanged
Impact
ConfidentialityLow
IntegrityLow
AvailabilityNone
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N
Affected Vendors & Products
roundcube1 product
webmail
Source: NVD CPE · 1 total CPE entries
Exploit & PoC Resources
NO KNOWN EXPLOITNo public exploit confirmed at this time
Exploit-DB
Offensive Security exploit database
GitHub PoC Search
Community PoC repositories
Rapid7 / Metasploit
Metasploit module search
PacketStorm
Security advisories & exploits
NVD Detail
Official NIST entry
MITRE CVE
CVE Program entry
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Official Patches & Advisories
All References (5)
Quick Facts
CVE IDCVE-2026-35540
CVSS Score6.5 / 10
SeverityMEDIUM
WeaknessCWE-669
CISA KEVNo
EPSS (30d)0.03%
Affected1 vendor
PublishedApr 3, 2026
Related CVEs (CWE-669)
Recommended Actions
- →Apply vendor patches immediately
- →Monitor CVE-2026-35540 in threat intel feeds
- →Review IDS/IPS signatures for exploitation attempts
Data sourced from NVD (NIST), CISA KEV, and EPSS (FIRST). Analysis generated by CTIWATCH.COM. CVE data is provided under the NVD usage policy.