Security readout for executives and security teams
Plain-English summary
CVE-2020-35505 is a QEMU denial-of-service flaw. A privileged user inside a guest VM could crash the QEMU process on the host when the am53c974 SCSI emulation handles a specific command path. The documented impact is availability, not data theft or host code execution.
Executive priority
Treat this as a service availability issue for QEMU-based virtualization. Prioritize patching shared, production, or customer-facing virtualization hosts, especially where guest administrators are not fully trusted. It is not evidenced as actively exploited in the supplied sources.
Technical view
The issue is a CWE-476 NULL pointer dereference in QEMU am53c974 SCSI host bus adapter emulation before 6.0.0, triggered while handling the Information Transfer command. Sources state a privileged guest user can crash the host-side QEMU process, causing denial of service.
Likely exposure
Exposure is most likely where QEMU versions before 6.0.0 are used with the am53c974 SCSI emulation reachable by guest systems. Risk is higher in multi-tenant or less-trusted guest environments where guest administrators should not be able to disrupt host workloads.
Exploitation context
The provided sources do not cite active exploitation, and the CVE is not marked as KEV. Exploitation requires privileged access inside a guest VM, limiting reach, but successful abuse can interrupt the affected virtual machine service by crashing QEMU.
Researcher notes
Evidence supports a local, guest-privileged denial-of-service condition tied to am53c974 SCSI emulation. The source bundle does not provide CVSS details, exploit maturity, or broader product impact beyond referenced vendor advisories, so exposure should be confirmed against local QEMU configuration and vendor packages.
Mitigation direction
- Upgrade QEMU to 6.0.0 or a vendor package that includes the fix.
- Apply relevant Debian, Gentoo, NetApp, or platform vendor security updates.
- Inventory VMs using am53c974 or related SCSI emulation.
- Restrict privileged guest access in less-trusted tenant environments.
- Monitor for unexpected QEMU process crashes until patched.
Validation and detection
- Check QEMU package versions on virtualization hosts.
- Review VM hardware definitions for am53c974 SCSI emulation exposure.
- Confirm vendor advisories or changelogs mention CVE-2020-35505 remediation.
- Review host logs for unexplained QEMU process termination events.
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-476: 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-2020-35505 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=1909769CVE 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
- [debian-lts-announce] 20220905 [SECURITY] [DLA 3099-1] qemu security updateCVE reference · mailing-list, x_refsource_MLIST
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.
NULL Pointer Dereference
NULL Pointer Dereference represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.