Security readout for executives and security teams
Plain-English summary
CVE-2020-35506 is a memory-safety flaw in QEMU's emulated am53c974 SCSI adapter. A privileged user inside a guest VM could crash the host-side QEMU process, disrupting that VM, and the source says code execution as the QEMU process may be possible.
Executive priority
Treat as high priority for virtualization platforms with untrusted or semi-trusted guest administrators. For single-tenant or tightly controlled VMs, urgency is lower but remediation should still be scheduled because host-side QEMU stability and process privileges are in scope.
Technical view
The issue is a CWE-416 use-after-free in QEMU am53c974 SCSI host bus adapter emulation before 6.0.0, triggered while handling the Information Transfer command, CMD_TI. The documented impact is host QEMU process denial of service or potential code execution with QEMU process privileges.
Likely exposure
Exposure is likely limited to environments running QEMU versions before 6.0.0 with the am53c974 SCSI emulation available to guests. Risk is higher in shared virtualization, hosted labs, or tenant-controlled VM environments where guest administrators are not fully trusted.
Exploitation context
The source bundle does not show CISA KEV listing or active exploitation. The attacker model is a privileged guest user. Public sources describe impact and the vulnerable component, but no reliable exploit status or broad in-the-wild activity is provided here.
Researcher notes
The affected surface is specific: QEMU am53c974 SCSI HBA emulation before 6.0.0 and CMD_TI handling. Evidence supports denial of service and potential code execution, but exploitability details, reliable exploit availability, and affected downstream product specifics are incomplete in the provided bundle.
Mitigation direction
- Upgrade QEMU to 6.0.0 or a vendor-fixed package version.
- Check Linux distribution and appliance vendor advisories for backported fixes.
- Disable or avoid exposing am53c974 SCSI emulation when not required.
- Prioritize shared or tenant-accessible virtualization hosts first.
- Review QEMU process isolation and least-privilege configuration.
Validation and detection
- Inventory QEMU versions on virtualization hosts and images.
- Identify VMs configured with am53c974 SCSI host bus adapter emulation.
- Confirm vendor package changelogs include the CVE-2020-35506 fix.
- Check whether untrusted users have privileged access inside affected guests.
- Verify monitoring covers unexpected QEMU process crashes.
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-416: 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 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-2020-35506 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://www.openwall.com/lists/oss-security/2021/04/16/3CVE reference · x_refsource_MISC
- https://bugzilla.redhat.com/show_bug.cgi?id=1909996CVE reference · x_refsource_MISC
- https://security.netapp.com/advisory/ntap-20210713-0006/CVE reference · x_refsource_CONFIRM
- GLSA-202208-27CVE reference · vendor-advisory, x_refsource_GENTOO
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.
Use After Free
Use After Free represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.