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CVE-2026-15256

MEDIUM 4.8 PoC AVAILABLE

Published 2026-08-06 · Last modified 2026-08-07

The Ninja Forms WordPress plugin before 3.14.10 does not prevent user-supplied query-string input, used to pre-populate a form field's default value, from being processed as a shortcode, allowing unauthenticated attackers to execute arbitrary shortcodes registered on the site when a form so configured is embedded on a public page.

EXPLOIT AVAILABLE

Public exploit or PoC code exists. Modeled probability is still low, but the barrier to attack is reduced — watch closely.

Exploitation likelihood

0.2%chance of exploitation in 30 days · 9th percentile

○ In CISA KEV ● Public exploit / PoC

Impact if exploited

4.8CVSS 3.1 · MEDIUM

  • ConfidentialityLow
  • IntegrityLow
  • AvailabilityNone

What an attacker needs

  • ✓Access: Reachable over the network — no local access needed
  • ✓Privileges: No account or privileges required
  • ✓User interaction: No user interaction needed
  • ⚠Complexity: Needs a race window or specific setup

✓ lowers the bar for an attacker · ⚠ raises it

Proof of concept & exploit code

Test against your own equipment

curl -s https://vulnpedia.com/cve/CVE-2026-15256/poc.jsonMachine-readable PoC index for this CVE (for automation).

Listed for defensive triage, patch verification, and authorized testing on systems you own. Machine-readable: /cve/CVE-2026-15256/poc.json

Affected

Vendors Unknown

Products Ninja Forms

Weakness (CWE)

  • CWE-74: Improper Neutralization of Special Elements in Output Used by a Downstream Component ('Injection')

CVSS vector

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

All CVSS metrics

  • MEDIUM 4.8 v3.1 · CNA Primary
    CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:N
  • MEDIUM 4.8 v3.1 · NVD Secondary
    CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:N

References

Exploits & PoC

Sources: NVD · CVE.org · EPSS