Security readout for executives and security teams
Plain-English summary
CVE-2021-47899 affects Mfscripts YetiShare File Hosting Script v5.1.0. Its remote URL upload feature can be abused to make the server access local files, potentially exposing sensitive system information. Public exploit information exists, but the provided sources do not show active exploitation or a confirmed vendor patch.
Executive priority
Treat this as a moderate, externally reachable application risk. Prioritize review if YetiShare v5.1.0 hosts customer files or runs on shared infrastructure. The lack of confirmed patch information means teams should verify vendor guidance and apply interim restrictions where practical.
Technical view
The issue is described as SSRF/local file access in the url_upload_handler endpoint via the remote upload url parameter. The CVSS v4.0 score is 6.9, with network attack vector, low complexity, no privileges, and no user interaction. The record lists CWE-434, though the described behavior is SSRF-style local file retrieval.
Likely exposure
Organizations running internet-accessible YetiShare File Hosting Script v5.1.0 are the primary concern, especially if remote URL upload is enabled. Exposure is narrower if the product is not deployed, is not public-facing, or the affected upload feature is unavailable.
Exploitation context
A public Exploit-DB reference is listed, so exploit details are publicly available. The source bundle does not indicate CISA KEV listing or confirmed active exploitation. Impact appears focused on reading local server files and possible related information disclosure.
Researcher notes
The provided record names v5.1.0 only. Do not generalize to other versions without vendor evidence. Public exploit availability increases validation urgency, but active exploitation is not evidenced. There is a taxonomy mismatch: CWE-434 is listed, while the description centers on SSRF/local file access.
Mitigation direction
- Identify any YetiShare File Hosting Script v5.1.0 deployments.
- Check Mfscripts/YetiShare guidance for fixed versions or vendor-recommended mitigations.
- If feasible, disable or restrict remote URL upload until guidance is confirmed.
- Limit server egress and local file access from the web application context.
- Prioritize remediation for internet-facing or shared-hosting deployments.
Validation and detection
- Confirm the installed YetiShare version from application inventory or administrative records.
- Determine whether remote URL upload is enabled and reachable externally.
- Review web logs for suspicious remote upload requests referencing local file schemes.
- Validate compensating controls in a staging environment, not against production blindly.
- Track CVE, VulnCheck, and vendor pages for patch or mitigation updates.
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 lookupCloud metadata behavior lookup
The CVE wording references SSRF or metadata access, so cloud discovery and credential material review may help. This is a Glexia inferred lookup path, not an official MITRE, ATT&CK, or CVE Program mapping.
Open ATT&CK lookupFile access behavior lookup
The CVE wording references file access or upload behavior, so file telemetry and web shell review may help. This is a Glexia inferred lookup path, not an official MITRE, ATT&CK, or CVE Program mapping.
Open ATT&CK lookupCVE-2021-47899 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
- Medium
- CVSS
- 6.9 (4.0)
- Known Exploited
- No
- Published
Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:L/VA:N/SC:L/SI:L/SA:L
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:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:L/VA:N/SC:L/SI:L/SA:L——Primary CVE scoreVulnerability scoring details
Base CVSS 4.0 score
6.9MediumVector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:L/VA:N/SC:L/SI:L/SA:L
Source materials
- CVE List V5 sourceCVE List V5
- ExploitDB-49534CVE reference · exploit
- Vendor HomepageCVE reference · product
- Software Product PageCVE reference · product
- VulnCheck Advisory: YetiShare File Hosting Script 5.1.0 Remote File Upload SSRF VulnerabilityCVE 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.