Security readout for executives and security teams
Plain-English summary
Samba could let a logged-in user perform file or directory metadata operations outside the intended shared folder. This matters where Samba shares enforce business or tenant boundaries. The provided sources do not include a CVSS score or active exploitation evidence.
Executive priority
Treat as a scheduled remediation item for Samba environments, with higher priority for shared file servers enforcing sensitive access boundaries or serving many authenticated users.
Technical view
CVE-2021-20316 is a Samba metadata handling flaw classified as CWE-362. An authenticated attacker with permission to read or modify share metadata may cause that operation to occur outside the share boundary. Samba before 4.15.0 is listed as affected; Samba 4.15.0 is listed as fixed.
Likely exposure
Exposure is most likely on Samba file servers running versions before 4.15.0, especially where authenticated users can access or change metadata on shared files or directories.
Exploitation context
The source bundle marks KEV as false and does not cite active exploitation. Exploitation requires authenticated access and relevant share metadata permissions, reducing internet-scale risk but leaving insider, compromised-account, and shared-environment risk.
Researcher notes
Evidence is limited to the bundle. The available description confirms a metadata boundary issue and CWE-362, but does not provide CVSS, detailed affected configurations, exploit maturity, or technical trigger conditions.
Mitigation direction
- Upgrade Samba to 4.15.0 or a vendor-supported fixed package.
- Review Samba, Red Hat, Debian, and Gentoo advisories for distribution-specific package status.
- Limit metadata read or modification rights on sensitive shares where practical.
- Audit Samba shares that separate tenants, departments, or trust zones.
Validation and detection
- Inventory Samba versions and flag servers running before 4.15.0.
- Check package manager advisory status for each Linux distribution in use.
- Review share permissions for users allowed to read or modify metadata.
- Confirm compensating controls where immediate upgrade is not possible.
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-362: 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 lookupCVE-2021-20316 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
- Unknown
- CVSS
- Not scored
- Known Exploited
- No
- Published
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 and timeline data
No CVSS vectors or timeline events were available in the normalized CVE source material.
Source materials
- CVE List V5 sourceCVE List V5
- https://bugzilla.samba.org/show_bug.cgi?id=14842CVE reference
- https://www.samba.org/samba/security/CVE-2021-20316.htmlCVE reference
- https://bugzilla.redhat.com/show_bug.cgi?id=2009673CVE reference
- https://access.redhat.com/security/cve/CVE-2021-20316CVE reference
- https://security-tracker.debian.org/tracker/CVE-2021-20316CVE reference
- GLSA-202309-06CVE 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.
Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition')
Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition') represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.