CVE-2026-1555
WebStack <= 1.2024 - Unauthenticated Arbitrary File Upload
CVE-2026-1555 is a critical vulnerability (CVSS 9.8) in Owen Webstack, published April 15, 2026. Public exploit code exists. EPSS puts the chance of exploitation in the next 30 days at 1.00%, the 63rd percentile. No source names a fixed version.
- Severity
- 9.8 CriticalCVSS 3.1, CVE List
- Exploit chance
- 1.00%EPSS, 63rd percentile
- Exploitation
- None known3 public exploits
- Fixed in
- No fix listedNo source names one
Description
The WebStack theme for WordPress is vulnerable to arbitrary file uploads due to missing file type validation in the io_img_upload() function in all versions up to, and including, 1.2024. This makes it possible for unauthenticated attackers to upload arbitrary files on the affected site's server which may make remote code execution possible.
Attack profile
How easy it is to exploit
- Attack vector
- Network
- Complexity
- Low
- Privileges needed
- None
- User interaction
- None
What an attacker can affect
- Confidentiality
- High
- Integrity
- High
- Availability
- High
Exploit likelihood
Affected products
Public exploits
Links only. Every CVE stores no exploit code.
| Source | Link | Date |
|---|---|---|
| PoC in GitHub | Nxploited/CVE-2026-1555 | 2026-04-17 |
| PoC in GitHub | katranSefa/CVE-2026-1555 | 2026-09-02 |
| PoC in GitHub | willygailo/WG-CVE-2026-1555-Linux | 2026-06-08 |
What each source reports
CVE List Score used
WebStack <= 1.2024 - Unauthenticated Arbitrary File Upload
The WebStack theme for WordPress is vulnerable to arbitrary file uploads due to missing file type validation in the io_img_upload() function in all versions up to, and including, 1.2024. This makes it possible for unauthenticated attackers to upload arbitrary files on the affected site's server which may make remote code execution possible.
- Record
CVE-2026-1555- CVSS 3.1
- 9.8 Critical
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H - Weakness
- CWE-434
- Updated
- 2026-11-02
EUVDEUVD-2026-22830
The WebStack theme for WordPress is vulnerable to arbitrary file uploads due to missing file type validation in the io_img_upload() function in all versions up to, and including, 1.2024. This makes it possible for unauthenticated attackers to upload arbitrary files on the affected site's server which may make remote code execution possible.
- Record
EUVD-2026-22830- CVSS 3.1
- 9.8 Critical
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H - Updated
- 2026-11-02
GitHub AdvisoriesGHSA-5c49-p8m3-fjh3
The WebStack theme for WordPress is vulnerable to arbitrary file uploads due to missing file type...
The WebStack theme for WordPress is vulnerable to arbitrary file uploads due to missing file type validation in the io_img_upload() function in all versions up to, and including, 1.2024. This makes it possible for unauthenticated attackers to upload arbitrary files on the affected site's server which may make remote code execution possible.
- Record
GHSA-5c49-p8m3-fjh3- CVSS 3.1
- 9.8 Critical
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H - Weakness
- CWE-434
- Updated
- 2026-11-02
NVD
The WebStack theme for WordPress is vulnerable to arbitrary file uploads due to missing file type validation in the io_img_upload() function in all versions up to, and including, 1.2024. This makes it possible for unauthenticated attackers to upload arbitrary files on the affected site's server which may make remote code execution possible.
- Record
CVE-2026-1555- CVSS 3.1
- 9.8 Critical
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H - Weakness
- CWE-434
- Updated
- 2026-11-02
OSV
WebStack <= 1.2024 - Unauthenticated Arbitrary File Upload
The WebStack theme for WordPress is vulnerable to arbitrary file uploads due to missing file type validation in the io_img_upload() function in all versions up to, and including, 1.2024. This makes it possible for unauthenticated attackers to upload arbitrary files on the affected site's server which may make remote code execution possible.
- Record
CVE-2026-1555- CVSS 3.1
- 9.8 Critical
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H - Weakness
- CWE-434
- Updated
- 2026-11-02
History
| Recorded | Changed | Sources |
|---|---|---|
| first indexed | CVE List, EUVD, GitHub Advisories, NVD, OSV, PoC in GitHub |
Dates are when Every CVE recorded each change. Upstream dates may differ.
References
wordfence.com/threat-intel/vulnerabilities/id/b97805de-1b47-4c9f-baae-2e37c1b78570?source=cve
github.com/owen0o0/WebStack/blob/master/inc/ajax.php
nvd.nist.gov/vuln/detail/CVE-2026-1555