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CVE-2026-16636Suited to automated attack · CISA

FluentSMTP <= 2.2.95 - Unauthenticated Stored Cross-Site Scripting via Recipient Display Name (to.name) in Email Logs

CVSS score

7.2

EPSS probability

%0.5

Risk score

0.0

Published

2 mo ago

OverviewPublic Exploits (0)NewsroomVulnerability Timeline
Patch status has not yet been verified

Resmî kaynaklarda yeterli kanıt bulunamadı. Bu sonuç “yama yok” anlamına gelmez.

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Vulnerability description

DayBreach CVE AI Research

CVE-2026-16636 has vendor, distribution, patch and security-source records on file. We can compare them and prepare an explanation linked to the evidence.

The FluentSMTP – WP SMTP Plugin with Amazon SES, SendGrid, MailGun, Postmark, Google and Any SMTP Provider plugin for WordPress is vulnerable to Stored Cross-Site Scripting via Recipient Display Name (to.name) in Email Logs in all versions up to, and including, 2.2.95 due to insufficient input sanitization and output escaping. This makes it possible for unauthenticated attackers to inject arbitrary web scripts in pages that will execute whenever a user accesses an injected page. The payload is delivered via an attacker-controlled recipient display name (to.name) in a wp_mail() call and does not fire in the log list view — only in the detail view when an administrator uses the Prev/Next navigation controls, as that path bypasses the escapeHtml pipeline used by the list view.

IMPACT: Affected Products and Software

Affected Products

The following products are affected by CVE-2026-16636 vulnerability. Where our threat engine knows the exact affected versions, they are listed below.

IDVENDORPRODUCTACTION
1wpmanageninjaFluentSMTP – WP SMTP Plugin with Amazon SES, SendGrid, Mailgun, Postmark, Cloudflare, toSend, Gmail and Any SMTP View
Total affected vendors: 1|Products: 1

RED HAT CSAF/VEX: Product Impact Check

Red Hat has not yet published a CSAF/VEX impact record for this CVE. This does not mean “not affected”.

SCORING: CVSS from Multiple Sources

CVSS Scores

The Common Vulnerability Scoring System is a standardised framework for assessing the severity of vulnerabilities in software and systems. We collect and display CVSS scores from several sources for each CVE.

SCOREVERSIONSEVERITYVECTORSOURCE
7.2CVSS V3_1HIGHCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:L/A:NCVE CNA
7.2CVSS V31HIGHCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:L/A:NNVD

Patch and Remediation Guide

Solution & Remediation Advisory

Patch status unknown

İncelenen resmî kaynaklarda yama durumu doğrulanamadı. Bu sonuç “yama yok” anlamına gelmez.

Confirm the affected product and version against the source evidence above.
Restrict access to internet-facing services and apply network segmentation.
Until a patch is confirmed, follow the vendor advisory; do not read an unknown status as “no patch”.
Monitor server logs and network endpoints for signs of anomalous execution.

Public exploit and active exploitation status

Verified exploit intelligence

No verified public PoC, exploit repository or Metasploit module has been found for this CVE yet.

Weakness Classification and Attack Patterns (CWE & CAPEC)

CWE - Common Weakness Enumeration

While CVE identifies specific instances of vulnerabilities, CWE categorises the common flaws or weaknesses that can lead to vulnerabilities. CVE-2026-16636 is associated with the following CWEs:

CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')

Common Attack Pattern Enumeration and Classification (CAPEC)

Common Attack Pattern Enumeration and Classification (CAPEC) stores attack patterns, which are descriptions of the common attributes and approaches employed by adversaries to exploit the CVE-2026-16636 weaknesses.

CAPEC-66: SQL InjectionCAPEC-126: Path TraversalCAPEC-28: OS Command Injection

Attack Vector and Accessibility

ExposureAğ üzerinden
PermissionsGerekmiyor
UserGerekmiyor

Official Sources and Advisories

https://www.wordfence.com/threat-intel/vulnerabilities/id/4ad3ed6b-19d4-47c7-a56c-54092c767fe9?source=cvevendor-advisoryhttps://plugins.trac.wordpress.org/browser/fluent-smtp/tags/2.2.95/assets/admin/js/fluent-mail-admin-app.jsvendor-advisoryhttps://plugins.trac.wordpress.org/browser/fluent-smtp/tags/2.2.95/app/Services/Mailer/BaseHandler.php#L357vendor-advisoryhttps://plugins.trac.wordpress.org/browser/fluent-smtp/tags/2.2.95/app/Models/Logger.php#L165vendor-advisoryhttps://plugins.trac.wordpress.org/browser/fluent-smtp/tags/2.2.95/app/Models/Logger.php#L310vendor-advisoryhttps://plugins.trac.wordpress.org/browser/fluent-smtp/tags/2.2.95/app/Services/Mailer/BaseHandler.php#L290vendor-advisoryhttps://plugins.trac.wordpress.org/changeset?reponame=&new=3635135%40fluent-smtp%2Ftags%2F2.3.0&old=3428610%40fluent-smtp%2Ftags%2F2.2.95vendor-advisoryhttps://plugins.trac.wordpress.org/changeset/3635135/fluent-smtp/trunk/assets/admin/js/fluent-mail-admin-app.jsvendor-advisoryhttps://plugins.trac.wordpress.org/changeset?old_path=%2Ffluent-smtp/tags/2.2.95&new_path=%2Ffluent-smtp/tags/2.3.0vendor-advisory

CVSS Vector Radar Chart

7.2 / 10
Attack VectorNetworkComplexityLowPrivilegesNoneUser Interact.NoneConfidentialityLowIntegrityNoneAvailabilityNone

Vulnerability Scoring Details

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:L/A:N
Attack VectorNetwork
Attack ComplexityLow
Privileges RequiredNone required
User InteractionNone required
Confidentiality (Gizlilik)Low
Integrity (Bütünlük)None
Availability (Erişilebilirlik)None

Yama durumu bilinmiyor

İncelenen resmî kaynaklarda yama durumu doğrulanamadı. Bu sonuç “yama yok” anlamına gelmez.

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Weakness Type (CWE & CAPEC)

CWE-79

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