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Vulnerabilities

Vulnerability · CVE-2026-2559

The Post SMTP plugin for WordPress is vulnerable to unauthorized modification of data due to a missing capability check on the function in all versions up to, and incl…

Published Mar 18, 2026 · catalog updated Jun 17, 2026 · the affected product

Check if you run it

No confirmed exploitation is on record for CVE-2026-2559. EPSS is 0.35%. Act only if a listed version of the affected product is installed.

Gaps on this record

  • No plain product name is stored. The page cannot tell you which product to check.
  • No vendor fix or required action is stored. Compare the linked advisory before you change production.
Severity
Medium5.3
Known exploitation
Not in CISA/VulnCheck KEV
EPSS
0.35%
Remediation
Version ranges on file
Affected products
stated named in the record

The Post SMTP plugin for WordPress is vulnerable to unauthorized modification of data due to a missing capability check on the function in all versions up to, and including, 3.8.0. This is due to the function being hooked to without any check or nonce verification. This makes it possible for authenticated attackers, with Subscriber-level access and above, to overwrite the site's Office 365 OAuth mail configuration (access token, refresh token, and user email) via a crafted URL. The configuration option is used during wizard setup of Microsoft365 SMTP, only available in the Pro option of the plugin. This could cause an Administrator to believe an attacker-controlled Azure app is their own, and lead them to connect the plugin to the attacker's account during configuration after upgrading to Pro.

Are you affected?

Enter the version you run. The result uses only the ranges stored on this record.

The check returns affected, not affected, or incomplete. It does not guess a version that is missing from the record.

  • stated named in the record<= 3.8.0

How to fix CVE-2026-2559

What to do

Three questions, each answered from this record only. Confirm the vendor advisory before you patch.

Should you patch?

No confirmed exploitation is on record for CVE-2026-2559. EPSS is 0.35%. Act only if a listed version of the affected product is installed.

Which versions are affected?

Compare what you have installed with named in the record <= 3.8.0. Compare the installed version with the linked vendor advisory before you change production.

What should an analyst verify?

CWE-862: Missing Authorization. EPSS 0.35%. There is no CISA KEV listing. No Exploit-DB or Metasploit reference is linked. Use the source links for the original advisory.

Technology hubs

WordPress security

Code

The project this record applies to. Exploit listings stay in References.

Timeline

Detection, updates, and resolution for this record.

  1. Mar 18, 2026 · NIST NVD

    Detected

    The Post SMTP plugin for WordPress is vulnerable to unauthorized modification of data due to a missing capability check on the function in all versions up to, and including, 3.8.0. This is due to the function being hooked to without any check or nonce verification. This makes it possible for authenticated attackers, with Subscriber-level access and above, to overwrite the site's Office 365 OAuth m

  2. Jun 17, 2026 · NIST NVD

    Updated

    The Post SMTP plugin for WordPress is vulnerable to unauthorized modification of data due to a missing capability check on the function in all versions up to, and including, 3.8.0. This is due to the function being hooked to without any check or nonce verification. This makes it possible for authenticated attackers, with Subscriber-level access and above, to overwrite the site's Office 365 OAuth m

Sources

  • CVE.orgVulnerability recordCVE-2026-2559

    Official CVE identifier

    cve.org
  • FIRST EPSSExploitation probabilityCVE-2026-2559

    30-day exploitation probability 0.4%

    first.org
  • NIST NVDVulnerability recordCVE-2026-2559

    The Post SMTP plugin for WordPress is vulnerable to unauthorized modification of data due to a missing capability check on the function in all versions up to, and including, 3.8.0. This is due to the function being hooked to withou

    nvd.nist.gov

References

Freshness

Last verified in this catalog Oct 18, 2026. Significant claims (KEV, EPSS, CVSS, affected ranges) come from the source rows above — open the original publisher for the authoritative advisory.