Security readout for executives and security teams
Plain-English summary
This vulnerability concerns Textpattern CMS and could let a logged-in user upload a PHP file that runs commands on the server. That can lead to full compromise of website data and availability. Public metadata is inconsistent about whether 4.8.3 is affected or the fixed version, so teams should verify their installed version against vendor guidance.
Executive priority
Treat as a high-priority website security issue, especially for public Textpattern sites with multiple users. Prioritize version verification, access restriction, and vendor-guided updating because compromise could affect confidentiality, integrity, and availability.
Technical view
CVE-2021-47888 is described as authenticated remote code execution via unrestricted upload of malicious PHP files, mapped to CWE-434. The CVSS 3.1 score is 8.8 with low attack complexity and low privileges required. Sources cite a public Exploit-DB entry, but CISA KEV status is false and no active exploitation is provided in the bundle.
Likely exposure
Internet-facing Textpattern installations are most exposed when attackers can obtain or already have valid user credentials with upload capability. Risk is higher where the web server can execute uploaded PHP content and administrative access is broadly granted.
Exploitation context
The issue requires authentication, but no user interaction. Public exploit material exists in Exploit-DB, increasing validation urgency. The provided sources do not establish active exploitation in the wild.
Researcher notes
The source bundle contains a version ambiguity: the description says versions prior to 4.8.3, while the title and affected entry reference 4.8.3. Do not assume fixed or affected status without checking vendor release information and the CVE record.
Mitigation direction
- Check Textpattern's official guidance and install the vendor-recommended supported release.
- Restrict Textpattern administrative access to trusted users and networks.
- Review upload permissions and disable unnecessary file upload capabilities.
- Prevent execution of uploaded PHP files where operationally feasible.
- Audit recent uploads and web logs for unexpected PHP files.
Validation and detection
- Inventory all Textpattern installations and record exact versions.
- Confirm whether each instance allows authenticated users to upload PHP files.
- Review user accounts with upload or administrative privileges.
- Check web-accessible upload directories for unexpected executable files.
- Monitor server logs for suspicious access to uploaded PHP files.
Public sources used
Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.
Conservative CVE-to-ATT&CK context
These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.
ATT&CK lookup starting points
Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.
CWE-434: File access and web shell behavior lookup
File traversal and upload weaknesses can lead teams to review file, web shell, execution, and collection telemetry. Open the exact CWE lookup page first, then review the ATT&CK searches from that MITRE weakness context. This is a Glexia lookup hint, not an official ATT&CK mapping.
Open ATT&CK lookupExecution behavior lookup
The CVE wording references code or command execution, so execution technique review may help defensive triage. This is a Glexia inferred lookup path, not an official MITRE, ATT&CK, or CVE Program mapping.
Open ATT&CK lookupCVE-2021-47888 mapping review
Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.
Open ATT&CK lookup- Severity
- High
- CVSS
- 8.8 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
CNA and ADP enrichment extracted from CVE v5
These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.
CVSS vector scores
1 official scoreWe collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H2.85.9Primary CVE scoreVulnerability scoring details
Base CVSS 3.1 score
8.8HighVector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Source materials
- CVE List V5 sourceCVE List V5
- ExploitDB-49620CVE reference · exploit
- Official Vendor HomepageCVE reference · product
- Textpattern Software Download PageCVE reference · product
- VulnCheck Advisory: Textpattern 4.8.3 - Remote code executionCVE reference · third-party-advisory
Products and packages named in the record
CWE details
CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.
Unrestricted Upload of File with Dangerous Type
Unrestricted Upload of File with Dangerous Type represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.