ReviewCritical

CVE-2026-16618

Improve SEO

The Improve SEO WordPress plugin through 2.0.11 does not properly validate uploaded files, checking only the file content type while writing the file with the attacker-supplied extension into a publicly accessible directory, allowing unauthenticated users to upload executable PHP files and achieve remote code execution.

CVSS
9.8
EPSS
0.46%
38.4% percentile
CISA KEV
Not listed
Published
2026.08.04
PRIORITY ASSESSMENT

Review

The CVSS severity warrants an early asset and exposure review.

Known exploitationNot established by KEV
Exploit probability0.46%
Technical severityCVSS 9.8

Vulnerability overview

The Improve SEO WordPress plugin through 2.0.11 does not properly validate uploaded files, checking only the file content type while writing the file with the attacker-supplied extension into a publicly accessible directory, allowing unauthenticated users to upload executable PHP files and achieve remote code execution.

Affected product and versions

Product
Improve SEO
Affected versions
<= 2.0.11
Fixed versions
No verified fixed-version field is available yet

Recommended response sequence

Confirm exposure before applying a vendor-supported change.

Full remediation guide
  1. 1
    Identify

    Confirm that Improve SEO and an affected version are present.

  2. 2
    Prioritize

    Combine exploitation signals with asset exposure and business criticality.

  3. 3
    Remediate

    Follow the vendor advisory or supported update path and preserve rollback options.

  4. 4
    Verify

    Recheck the version, service health, access paths, and relevant logs.

Technical data

CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
CWE
CWE-434