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Fencer Vulns
medium 4.3

CVE-2021-4407 json

Custom Banners <= 3.2.2 - Cross-Site Request Forgery Bypass

published 2023-07-12 3 y ago modified 2026-06-17 4 mo ago also EUVD-2021-34234

cvss
4.3
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.4%
EPSS 0.4% chance of exploitation in 30 days, percentile 32%
public exploits
0
none known

Summary

The Custom Banners plugin for WordPress is vulnerable to Cross-Site Request Forgery in versions up to, and including, 3.2.2 This is due to missing or incorrect nonce validation on the saveCustomFields() function. This makes it possible for unauthenticated attackers to save custom fields via a forged request granted they can trick a site administrator into performing an action such as clicking on a link.

Patch / fix

CISA SSVC

Exploitation
none
Automatable
no
Technical impact
partial
Assessed
2 y ago

Exploit prediction

0.38% chance of exploitation in the next 30 days, higher than 32% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 3.1 4.3 CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:N

Affected products

  • ghuger Custom Banners

Classification

Weakness
  • CWE-352 Cross-Site Request Forgery
Technology feeds

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.