Security readout for executives and security teams
Plain-English summary
This vulnerability is a confidentiality issue in Linux kernel handling of an Intel CPU speculative-execution mitigation. In a narrow virtualization scenario, a guest may skip buffer-clearing that should protect sensitive data. The issue is rated medium, but exposure matters most for shared or multi-tenant virtualization on affected Intel Cascade Lake hosts with TSX enabled.
Executive priority
Treat this as a targeted remediation item for virtualization platforms, not a broad internet emergency. Prioritize systems hosting untrusted tenants or sensitive workloads, because the impact is data confidentiality rather than integrity or availability.
Technical view
Linux kernels before 5.5 mishandled the CVE-2019-11135 TAA mitigation when guests saw MDS_NO=1 on TAA-affected CPUs. On Cascade Lake hosts with TSX enabled, guests could omit VERW-based buffer clearing, leaving a potential local information disclosure path. CVSS is 5.5: local, low privilege, no user interaction, confidentiality impact only.
Likely exposure
Most relevant to organizations running virtualized workloads on Intel Cascade Lake hosts where TSX is enabled. The source bundle identifies Linux kernel versions before 5.5 as affected. Non-virtualized systems or systems without the described CPU and TSX conditions are not evidenced as exposed by these sources.
Exploitation context
The bundle does not cite active exploitation, and KEV is false. Exploitation is local and privilege-requiring per CVSS, with confidentiality impact. The issue is operationally important where untrusted or differently trusted guests share affected virtualization hosts.
Researcher notes
Evidence is specific to TAA/MDS mitigation interaction in Linux guests on Cascade Lake hosts with TSX enabled. The source bundle does not provide proof-of-concept details or exploitation evidence. Validate real exposure through CPU capability reporting, kernel version, vendor backports, and hypervisor guest CPU flag presentation.
Mitigation direction
- Upgrade affected Linux kernels to a vendor-supported fixed release or 5.5-or-later lineage.
- Review Red Hat or Linux vendor advisories for backported fixes on supported distributions.
- Review Intel TAA guidance before changing TSX or CPU mitigation settings.
- Prioritize shared, multi-tenant, and sensitive virtualization hosts first.
- Avoid assuming protection from MDS_NO exposure without vendor validation.
Validation and detection
- Inventory virtualization hosts for Cascade Lake CPUs and TSX enablement.
- Identify Linux kernel versions before 5.5, including vendor backport status.
- Check whether guests are exposed to MDS_NO=1 on TAA-affected hosts.
- Confirm vendor advisories list CVE-2019-19338 as fixed or not applicable.
- Document any compensating CPU mitigation or TSX configuration decisions.
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-203: Information exposure and cloud metadata lookup
Information exposure and SSRF weaknesses can make discovery, cloud metadata, and credential material review relevant. 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 lookupCWE-385: 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-2019-19338 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
- 5.5 (3.0)
- Known Exploited
- No
- Published
Vector: CVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N
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:3.0/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N1.83.6Primary CVE scoreVulnerability scoring details
Base CVSS 3.0 score
5.5MediumVector: CVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N
Source materials
- CVE List V5 sourceCVE List V5
- https://www.openwall.com/lists/oss-security/2019/12/10/3CVE reference · x_refsource_MISC
- https://bugzilla.redhat.com/show_bug.cgi?id=CVE-2019-19338CVE reference · x_refsource_CONFIRM
- https://software.intel.com/security-software-guidance/insights/deep-dive-intel-transactional-synchronization-extensions-intel-tsx-asynchronous-abortCVE reference · x_refsource_MISC
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.
Observable Discrepancy
Observable Discrepancy represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.
Covert Timing Channel
Covert Timing Channel represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.