Subscribe to Comments 2.3 — 2.3.2 - Authenticated (Author+) Arbitrary Email Header Injection
CVE-2026-91831Published · Updated Action summary
Affected: 2.3 – 2.3.2Update to 2.3.3 or newer
All remediation steps- Severity
- Medium4.3
- CVSS
- 4.3CVSS 3.1 · CNA (Wordfence)
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:NWhat does this vector mean?
AV:NAttack vector- Network
AC:LAttack complexity- Low
PR:LPrivileges required- Low
UI:NUser interaction- None
S:UScope- Unchanged
C:NConfidentiality- None
I:LIntegrity- Low
A:NAvailability- None
- Weakness
- CWE-20 Improper Input Validation
- Required access
- Unknown
- Exploit prediction (EPSS)
- 0.2% chance in 30 days5th percentile
- CISA KEV
- Not listed
On this page8
Am I affected?
Subscribe to Comments subscribe-to-comments
- Affected2.3 – 2.3.2
- Patched in2.3.3
Update to 2.3.3 or newer.
You are affected if you run 2.3 – 2.3.2. Version 2.3.3 and later are not affected by this issue.
- Check your version: in wp-admin go to Plugins → Installed Plugins and read the version under Subscribe to Comments.
- No admin access? Run a passive check of your site. It reads public files only.
What to do
- Update to version 2.3.3, or a newer patched version
- Rotate administrator passwords and application secrets if the site ran a vulnerable version while publicly reachable.
- Watch Subscribe to Comments to get an email when the next vulnerability is published.
Advisory
Source description from Wordfence Intelligence, credited to Het Kalariya.
The Subscribe to Comments plugin for WordPress is vulnerable to Email Header Injection in versions 2.3 through 2.3.2. This is due to missing newline sanitization on the notification sender-name setting before it is used in e-mail headers, combined with the absence of type-enforcement guards that prevented sanitize_text_field() from running reliably on the name field. This makes it possible for authenticated attackers, with author-level access and above, to inject arbitrary e-mail headers, such as a hidden Bcc field or a spoofed sender address, into notification e-mails sent to subscribers. The attacker must hold at least Author-level access to reach the settings form.
Exploits & references
Proof-of-concept & detection
No public proof-of-concept or detection template is known for this vulnerability.
Advisories & patches
- Advisorywordfence.com
Related CVEs
More in Subscribe to Comments
All 7| Severity | Vulnerability | CVE | Published |
|---|---|---|---|
| Medium5.3 | Unauthenticated Information Exposure ≤2.3.2Update to 2.3.3 | CVE-2026-91830 | |
| Medium6.1 | Reflected Cross-Site Scripting ≤2.3.2Update to 2.3.3 | CVE-2026-91829 | |
| Medium5.4 | Authenticated (Author+) Stored Cross-Site Scripting ≤2.3.1No patch available | CVE-2026-66706 | |
| Medium6.1 | Reflected Cross-Site Scripting ≤2.3Update to 2.3.1 | CVE-2024-8792 | |
| High7.2 | Local File Includion ≤2.1.2Update to 2.3 | CVE-2015-10133 |
- Medium5.3Unauthenticated Information Exposure
≤2.3.2Update to 2.3.3
- Medium6.1Reflected Cross-Site Scripting
≤2.3.2Update to 2.3.3
- Medium5.4Authenticated (Author+) Stored Cross-Site Scripting
≤2.3.1No patch available
- Medium6.1Reflected Cross-Site Scripting
≤2.3Update to 2.3.1
- High7.2Local File Includion
≤2.1.2Update to 2.3
Timeline
CVE published
Severity medium, CVSS 4.3
Record last updated
Sources & licenses
Wordfence record- Vulnerability data
- Wordfence Intelligence. Copyright 2012-2026 Defiant Inc. Licensed under the CC BY-SA 4.0.
- CVE® identifiers
- Copyright 1999-2026 The MITRE Corporation. Used under the CVE Program. CVE® is a registered trademark of The MITRE Corporation.
- CVSS / CWE
- National Vulnerability Database (NVD), shown unmodified. This product uses the NVD API but is not endorsed or certified by the NVD.
- EPSS
- Exploit Prediction Scoring System by FIRST.org.
- VulnCrest content
- Summary, remediation guidance and page layout © VulnCrest. Not sourced from NVD.