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NVD / CVE Program· CNA Wordfence

CVE-2021-34648: Ninja Forms <= 3.5.7 Unprotected REST-API to Email Injection

Noroxi assessment

Priority: Monitor (action score 17/100)

  • The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
  • Probability of exploitation in the next 30 days: 0.65% (FIRST EPSS); higher than 51.7% of all records.
  • Anyone who can reach it over the internet can trigger it. A low-privileged account is enough. No user action is required. No special conditions are required; it is repeatable.
  • According to the record, no fixed version is available yet.
  • Severity is disputed: the assigning authority (CNA) scores it 6.4, NVD 4.3.

Low priority for now. Update when a fix is released; follow the vendor's advisory.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

The Ninja Forms WordPress plugin is vulnerable to arbitrary email sending via the trigger_email_action function found in the ~/includes/Routes/Submissions.php file, in versions up to and including 3.5.7. This allows authenticated attackers to send arbitrary emails from the affected server via the /ninja-forms-submissions/email-action REST API which can be used to socially engineer victims.

MediumCVSS 4.3 · v3.1—No exploit No fix recorded
Published
Sep 22, 2021
Updated
Jun 16, 2026
EPSS
0.6% · 51th percentile

Report tools

JSON

Action score

17

Monitor

Low priority for now.

CVSS
17 / 40 · 4.3 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.6%

CISA SSVC decision

Exploitation
none
Automatable
no
Technical impact
partial

Vulnrichment: CISA's decision-tree inputs.

CNA vs NVD score

NVD
4.3
CNA · Wordfence
6.4
2.1 point gap

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:L/A:N

The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.

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Is Ninja Forms – Contact Form Builder with Calculators, Quizzes, Signatures & AI Form Builder on your site?

When you'll hear from us

  • when it enters CISA KEV
  • when exploit code appears or is weaponized
  • when the record is updated (including a fixed version)
  • when EPSS rises 20 points in a week

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Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

VendorProduct
ninjaformsninja forms

Affected versions

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

  • ninjaforms ninja formsup to 3.5.7 inclusive

Versions reported by the vendor

Affected version ranges reported by the assigning authority (Wordfence). Independent of NVD's CPE analysis and usually ahead of it.

  • Saturday Drive Ninja Forms

    • 3.5.7 and later · up to and including 3.5.7affected

Same product

ninjaforms: all records

Other highest-scoring records for the same primary product.

  • CVE-2016-1209The Ninja Forms plugin before 2.9.42.1 for WordPress allows remote attackers to conduct PHP object injection attacks via crafted serialized
    60This week
  • CVE-2025-9083Ninja-forms < 3.11.1 - Unauthenticated PHP Objection
    39Monitor
  • CVE-2024-37934WordPress Ninja Forms plugin <= 3.8.4 - Subscriber+ Arbitrary Shortcode Execution vulnerability
    39Monitor

Published before and after this one in the same product

  • ← EarlierCVE-2021-24166Apr 5, 2021 · Ninja Forms < 3.4.34 - CSRF to OAuth Service Disconnection
    21Monitor
  • ← EarlierCVE-2021-34647Sep 22, 2021 · Ninja Forms <= 3.5.7 Sensitive Information Disclosure
    26Monitor
  • Later →CVE-2021-24889Nov 29, 2021 · Ninja Forms < 3.6.4 - Admin+ SQL Injection
    28Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

No fix version is recorded for this entry. Check the references for vendor advisories.

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

No dated events beyond publication.

No history yet (it accumulates with the daily EPSS job).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

No commit or PR link among the references.

Credits

All researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

No nightly-computed relations.

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

—

Bug bounty scope

No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).

Technical details

Attack conditions

  • Anyone who can reach it over the internet can trigger it.
  • A low-privileged account is enough.
  • No user action is required.
  • No special conditions are required; it is repeatable.

If successful

Confidentiality
none
Integrity
low · data or configuration can be modified
Availability
none
Attack vector
Network
Attack complexity
Low
Privileges required
Low
User interaction
None
Scope
Unchanged
Confidentiality impact
None
Integrity impact
Low
Availability impact
None

Weakness class (CWE)

CWE-863 · Incorrect Authorization

CVSS vector

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N

nvd-primary

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

MITRE has no CAPEC/ATT&CK mapping for this CWE.

Change log

No changes recorded on tracked fields yet. Score, KEV, exploit maturity and fix status changes appear here.

References

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records