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Vulnerability Details :

CVE-2026-9818

Summary
Assigner-OCD
Assigner Org ID-6064c9f1-42e5-4cc5-a67a-1636d7a9d3fd
Published At-28 May, 2026 | 12:16
Updated At-28 May, 2026 | 13:24
Rejected At-
Credits

Roundcube Local/Private URL Fetch Bypass

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.

Vendors
-
Not available
Products
-
Metrics (CVSS)
VersionBase scoreBase severityVector
Weaknesses
Attack Patterns
Solution/Workaround
References
HyperlinkResource Type
EPSS History
Score
Latest Score
-
N/A
No data available for selected date range
Percentile
Latest Percentile
-
N/A
No data available for selected date range
Stakeholder-Specific Vulnerability Categorization (SSVC)
▼Common Vulnerabilities and Exposures (CVE)
cve.org
Assigner:OCD
Assigner Org ID:6064c9f1-42e5-4cc5-a67a-1636d7a9d3fd
Published At:28 May, 2026 | 12:16
Updated At:28 May, 2026 | 13:24
Rejected At:
▼CVE Numbering Authority (CNA)
Roundcube Local/Private URL Fetch Bypass

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.

Affected Products
Vendor
Roundcube Webmail ProjectRoundcube
Product
Webmail
Repo
https://github.com/roundcube/roundcubemail/
Default Status
unaffected
Versions
Affected
  • From 0 before 1.6.16 (git)
    • -> unaffectedfrom1.6.16
  • From 1.7.0 before 1.7.1 (git)
    • -> unaffectedfrom1.7.1
Problem Types
TypeCWE IDDescription
CWECWE-184CWE-184 Incomplete list of disallowed inputs
Type: CWE
CWE ID: CWE-184
Description: CWE-184 Incomplete list of disallowed inputs
Metrics
VersionBase scoreBase severityVector
3.14.7MEDIUM
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:N/I:L/A:N
Version: 3.1
Base score: 4.7
Base severity: MEDIUM
Vector:
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:N/I:L/A:N
Metrics Other Info
Impacts
CAPEC IDDescription
CAPEC-554CAPEC-554 Functionality Bypass
CAPEC-664CAPEC-664 Server Side Request Forgery
CAPEC ID: CAPEC-554
Description: CAPEC-554 Functionality Bypass
CAPEC ID: CAPEC-664
Description: CAPEC-664 Server Side Request Forgery
Solutions

Upgrade to Roundcube Webmail 1.6.16 or 1.7.1

Configurations
Workarounds
Exploits
Credits
finder
Guillaume Meunier from Orange Cyberdefense CERT VOC Team
Timeline
EventDate
Replaced By
Rejected Reason
References
HyperlinkResource
https://github.com/roundcube/roundcubemail/releases/tag/1.7.1
patch
https://github.com/roundcube/roundcubemail/releases/tag/1.6.16
patch
https://github.com/roundcube/roundcubemail/commit/faf867432f51ebbe100382a70a9e3c042415ee1b
patch
https://github.com/roundcube/roundcubemail/commit/7b52353653a67e6073b97d70eb94047132b78556
patch
https://advisories.orangecyberdefense.com/advisories/163
third-party-advisory
Hyperlink: https://github.com/roundcube/roundcubemail/releases/tag/1.7.1
Resource:
patch
Hyperlink: https://github.com/roundcube/roundcubemail/releases/tag/1.6.16
Resource:
patch
Hyperlink: https://github.com/roundcube/roundcubemail/commit/faf867432f51ebbe100382a70a9e3c042415ee1b
Resource:
patch
Hyperlink: https://github.com/roundcube/roundcubemail/commit/7b52353653a67e6073b97d70eb94047132b78556
Resource:
patch
Hyperlink: https://advisories.orangecyberdefense.com/advisories/163
Resource:
third-party-advisory
▼Authorized Data Publishers (ADP)
CISA ADP Vulnrichment
Affected Products
Metrics
VersionBase scoreBase severityVector
Metrics Other Info
Impacts
CAPEC IDDescription
Solutions
Configurations
Workarounds
Exploits
Credits
Timeline
EventDate
Replaced By
Rejected Reason
References
HyperlinkResource
Information is not available yet
▼National Vulnerability Database (NVD)
nvd.nist.gov
Source:6064c9f1-42e5-4cc5-a67a-1636d7a9d3fd
Published At:28 May, 2026 | 13:16
Updated At:28 May, 2026 | 13:16

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.

CISA Catalog
Date AddedDue DateVulnerability NameRequired Action
N/A
Date Added: N/A
Due Date: N/A
Vulnerability Name: N/A
Required Action: N/A
Metrics
TypeVersionBase scoreBase severityVector
Secondary3.14.7MEDIUM
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:N/I:L/A:N
Type: Secondary
Version: 3.1
Base score: 4.7
Base severity: MEDIUM
Vector:
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:N/I:L/A:N
CPE Matches
Weaknesses
CWE IDTypeSource
CWE-184Secondary6064c9f1-42e5-4cc5-a67a-1636d7a9d3fd
CWE ID: CWE-184
Type: Secondary
Source: 6064c9f1-42e5-4cc5-a67a-1636d7a9d3fd
Evaluator Description
Evaluator Impact

Evaluator Solution

Vendor Statements
References
HyperlinkSourceResource
https://advisories.orangecyberdefense.com/advisories/1636064c9f1-42e5-4cc5-a67a-1636d7a9d3fd
N/A
https://github.com/roundcube/roundcubemail/commit/7b52353653a67e6073b97d70eb94047132b785566064c9f1-42e5-4cc5-a67a-1636d7a9d3fd
N/A
https://github.com/roundcube/roundcubemail/commit/faf867432f51ebbe100382a70a9e3c042415ee1b6064c9f1-42e5-4cc5-a67a-1636d7a9d3fd
N/A
https://github.com/roundcube/roundcubemail/releases/tag/1.6.166064c9f1-42e5-4cc5-a67a-1636d7a9d3fd
N/A
https://github.com/roundcube/roundcubemail/releases/tag/1.7.16064c9f1-42e5-4cc5-a67a-1636d7a9d3fd
N/A
Hyperlink: https://advisories.orangecyberdefense.com/advisories/163
Source: 6064c9f1-42e5-4cc5-a67a-1636d7a9d3fd
Resource: N/A
Hyperlink: https://github.com/roundcube/roundcubemail/commit/7b52353653a67e6073b97d70eb94047132b78556
Source: 6064c9f1-42e5-4cc5-a67a-1636d7a9d3fd
Resource: N/A
Hyperlink: https://github.com/roundcube/roundcubemail/commit/faf867432f51ebbe100382a70a9e3c042415ee1b
Source: 6064c9f1-42e5-4cc5-a67a-1636d7a9d3fd
Resource: N/A
Hyperlink: https://github.com/roundcube/roundcubemail/releases/tag/1.6.16
Source: 6064c9f1-42e5-4cc5-a67a-1636d7a9d3fd
Resource: N/A
Hyperlink: https://github.com/roundcube/roundcubemail/releases/tag/1.7.1
Source: 6064c9f1-42e5-4cc5-a67a-1636d7a9d3fd
Resource: N/A

Change History

0
Information is not available yet

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