Security readout for executives and security teams
Plain-English summary
CVE-2018-9386 is a local Android kernel privilege issue in an HTC reboot_block driver. The source says a missing bounds check could allow a stack buffer overflow. It requires existing System execution privileges and no user interaction, so urgency depends on whether managed devices include this driver and remain unpatched.
Executive priority
Treat this as a moderate mobile platform hygiene issue. It is not remotely exploitable based on the provided evidence, but it could deepen compromise on affected devices where an attacker already has high local privileges. Prioritize unsupported or legacy Android fleets.
Technical view
The issue is in reboot_block_command in the htc reboot_block driver. CVE metadata classifies it as CWE-120 with CVSS 6.7, AV:L/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H. Impact is local escalation of privilege with high confidentiality, integrity, and availability impact.
Likely exposure
Evidence identifies Android Kernel and an HTC reboot_block driver, with a Pixel security bulletin reference. The bundle does not enumerate specific device models, OEM builds, or exact fixed versions. Exposure should be assessed against Android devices that include this driver and have not received the relevant June 2018 security update.
Exploitation context
The bundle does not indicate active exploitation, and KEV is false. Exploitation is described as local, low complexity, requiring high privileges and no user interaction. This is most relevant when an attacker or malicious component already has elevated local execution on an affected Android device.
Researcher notes
The source bundle is sparse: it provides the vulnerable function, driver, CWE, CVSS vector, and Android bulletin reference, but not a commit, patch diff, device list, or proof of exploitation. Avoid broad product claims beyond Android kernel builds containing the HTC reboot_block driver.
Mitigation direction
- Review vendor or OEM guidance for CVE-2018-9386 and the June 2018 Android/Pixel bulletin.
- Update affected Android devices to a build containing the relevant security fix.
- Prioritize remediation for devices that are unsupported or cannot receive security updates.
- Restrict administrative, debugging, and System-level access on managed Android devices.
Validation and detection
- Inventory Android devices and record OS build, kernel, OEM, and security patch level.
- Check whether the htc reboot_block driver is present in relevant device kernels.
- Compare device patch levels against the June 2018 Android/Pixel security bulletin.
- Confirm unsupported devices are isolated, replaced, or formally risk accepted.
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-120: 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-2018-9386 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
- 6.7 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H
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:L/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H0.85.9Primary CVE scoreVulnerability scoring details
Base CVSS 3.1 score
6.7MediumVector: CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H
Source materials
- CVE List V5 sourceCVE List V5
- https://source.android.com/security/bulletin/pixel/2018-06-01CVE reference
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.
Buffer Copy without Checking Size of Input ('Classic Buffer Overflow')
Buffer Copy without Checking Size of Input ('Classic Buffer Overflow') represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.