PatchTheCVECVE-2021-39320: The underConstruction plugin <= 1.18 for WordPress echoes out the raw value of `$GLOBALS['PHP_SELF']` in the u
CVE-2021-39320 is a medium-severity flaw (CVSS 6.1) affecting underconstruction. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.
The underConstruction plugin <= 1.18 for WordPress echoes out the raw value of `$GLOBALS['PHP_SELF']` in the ucOptions.php file. On certain configurations including Apache+modPHP, this makes it possible to use it to perform a reflected Cross-Site Scripting attack by injecting malicious code in the request path.
Why this priority
- No elevated risk signals yet
A fixed release or distro patch exists.
Risk facts
| CVSS score | 6.1 (Medium) |
| Attack vector | Network (remote) |
| Attack complexity | Low |
| Privileges needed | None |
| User interaction | Required |
| EPSS exploit chance | 2.3% (top 17%) |
| CISA exploited list | No |
| Weakness | CWE-79 |
| Published | 2021-09-01 |
| Last modified | 2026-06-17 |
Last updated 2026-06-17 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score
Am I affected?
Timeline
- Published CVE record published
- Updated Record last modified
Public exploits and detection
Public code exists for this CVE. Treat unpatched systems as at risk, and only run PoCs in a lab.
- Nuclei scan template: WordPress Under Construction <1.19 - Cross-Site Scripting
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.
Quick answers
How do I fix CVE-2021-39320?
underconstruction: upgrade to 1.19. Exact commands for each OS are on this page.
Is CVE-2021-39320 being exploited?
CVE-2021-39320 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.
What does CVE-2021-39320 affect?
CVE-2021-39320 affects underconstruction. Severity is medium (CVSS 6.1). The underConstruction plugin <= 1.18 for WordPress echoes out the raw value of `$GLOBALS['PHP_SELF']` in the ucOptions.php file. On certain configurations including Apache+modPHP, this makes it possible to use it to perform a reflected Cros
How urgent is CVE-2021-39320?
Priority 42/100. No elevated risk signals yet.
Software pages
WordPress vulnerabilities · PHP vulnerabilities
Related CVEs
- CVE-2022-1896 MEDIUM 4.8 UPGRADE The underConstruction WordPress plugin before 1.21 does not sanitise or escape the "Display a custom page usin
- CVE-2022-1895 MEDIUM 4.3 UPGRADE The underConstruction WordPress plugin before 1.20 does not have CSRF check in place when deactivating the con