Security readout for executives and security teams
Plain-English summary
Apache Zeppelin 0.9.0 and earlier can allow arbitrary file deletion through improper input validation in the “Move folder to Trash” feature. Business impact is loss or disruption of files accessible to the Zeppelin process, not data theft. The CVSS score is medium, but internet exposure or sensitive notebook environments raise urgency.
Executive priority
Treat this as a moderate-priority cleanup item, escalated if Zeppelin is internet-facing or handles sensitive analytics assets. The main risk is unauthorized deletion or disruption, so focus on exposure reduction, version confirmation, and vendor-guided remediation.
Technical view
CVE-2021-28655 is a CWE-20 input validation flaw in Apache Zeppelin’s folder trash workflow. The provided CVSS vector is network-accessible, low complexity, no privileges, and no user interaction, with low integrity and availability impact. Sources do not name a fixed version or detailed mitigation beyond the vendor advisory reference.
Likely exposure
Organizations running Apache Zeppelin 0.9.0 or prior are potentially exposed, especially if Zeppelin is reachable from untrusted networks. Exposure depends on deployment, process file permissions, and whether the vulnerable folder-to-trash functionality is accessible.
Exploitation context
The source bundle does not indicate active exploitation, and KEV is false. The CVSS vector suggests remote attackability without authentication, but no exploit details, proof of concept, or observed campaign evidence is provided in the cited sources.
Researcher notes
The public bundle is limited. It identifies improper input validation in the trash feature and affected versions as 0.9.0 and prior, but does not provide patch version, exploit details, or operational prerequisites. Avoid assuming broader Zeppelin components or unrelated Apache products are affected.
Mitigation direction
- Inventory Apache Zeppelin deployments and confirm exact versions.
- Prioritize review of any Zeppelin 0.9.0 or earlier instance.
- Check Apache’s advisory for fixed release and upgrade guidance.
- Restrict Zeppelin access to trusted networks and authenticated users.
- Limit filesystem permissions for the Zeppelin runtime account.
- Ensure recoverable backups for files reachable by Zeppelin.
Validation and detection
- Confirm whether Apache Zeppelin is installed and externally reachable.
- Verify installed Zeppelin version against 0.9.0 and earlier.
- Review runtime user permissions on sensitive directories.
- Check file deletion logs or filesystem audit records for anomalies.
- Confirm remediation against Apache’s published advisory.
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-20: Exact CWE lookup
Use the exact CWE identifier as the starting point before reviewing related ATT&CK behavior. 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 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-2021-28655 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
- 6.5 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A: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:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:L3.92.5Primary CVE scoreVulnerability scoring details
Base CVSS 3.1 score
6.5MediumVector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:L
Source materials
- CVE List V5 sourceCVE List V5
- https://lists.apache.org/thread/bxs056g3xlsofz0jb3wny9dw4llwptd2CVE reference · vendor-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.
Improper Input Validation
Improper Input Validation represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.