MetForm < 4.1.9 - Unauthenticated Email Header Injection via Notification Reply-To
Priority LOW 22CWE-93Published · Updated
Key facts
- Attack vector
- Network
- Privileges required
- None
- User interaction
- None
- Attack complexity
- High
- Impact type
- —
- Confidentiality · integrity · availability
- Low · Low · None
- Fix status
- Fixed
Attack profile from CVSS 3.1 · CNA. Fix status from CNA.
Summary
The MetForm WordPress plugin before 4.1.9 does not properly neutralize newline characters in user-submitted values that are placed into notification email headers, allowing unauthenticated attackers to inject additional email headers, such as Bcc, into the emails the site sends when a submitted field value is configured to populate a header.
Why it matters now
Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00243 15th percentileScored 2026-11-07
Public exploit Yes 1 exploit referenceTagged by the CNA
Fix Fixed MetForm (Unknown): 4.1.9
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- None
- Automatable
- No
- Technical impact
- Partial
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| Unknown | MetForm | before 4.1.9 | 4.1.9 | Patch available | CNA |
- MetForm VendorUnknown Affected before 4.1.9 Fixed in 4.1.9 Patch available CNA
Remediation
- Fix · CNA MetForm (Unknown) Fixed in 4.1.9
Timeline
- 2026-10-02 Threatist record created from CVE-2026-86813
- 2026-10-03 Alias added: GHSA-687m-wfrp-8mxf
References
Sources
- CVE-2026-86813 · CVE Program
- CVE-2026-86813 · NVD
- FIRST EPSS
- GHSA-687m-wfrp-8mxf · GitHub Advisory Database · CC BY 4.0
This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences