Security Vulnerability Reporting


Vulnerabilities to the Zephyr project may be reported via email to the mailing list. These reports will be acknowledged and analyzed by the security response team within 1 week. Each vulnerability will be entered into the Zephyr Project security advisory GitHub. The original submitter will be granted permission to view the issues that they have reported.

Security Issue Management

Issues within this bug tracking system will transition through a number of states according to this diagram:

digraph { node [style = rounded]; init [shape = point]; New [shape = box]; Triage [shape = box]; { rank = same; rankdir = LR; Assigned [shape = box]; Rejected [shape = box]; } Review [shape = box]; Accepted [shape = box]; Public [shape = box]; init -> New; New -> Triage; Triage -> Rejected [dir = both]; Triage -> Assigned; Assigned -> Review [dir = both]; Review -> Accepted; Review -> Rejected; Accepted -> Public; }

  • New: This state represents new reports that have been entered directly by a reporter. When entered by the response team in response to an email, the issue shall be transitioned directly to Triage.

  • Triage: This issue is awaiting Triage by the response team. The response team will analyze the issue, determine a responsible entity, assign it to that individual, and move the issue to the Assigned state. Part of triage will be to set the issue’s priority.

  • Assigned: The issue has been assigned, and is awaiting a fix by the assignee.

  • Review: Once there is a Zephyr pull request for the issue, the PR link will be added to a comment in the issue, and the issue moved to the Review state.

  • Accepted: Indicates that this issue has been merged into the appropriate branch within Zephyr.

  • Public: The embargo period has ended. The issue will be made publicly visible, the associated CVE updated, and the vulnerabilities page in the docs updated to include the detailed information.

The security advisories created are kept private, due to the sensitive nature of security reports. The issues are only visible to certain parties:

  • Members of the PSIRT mailing list

  • the reporter

  • others, as proposed and ratified by the Zephyr Security Subcommittee. In the general case, this will include:

    • The code owner responsible for the fix.

    • The Zephyr release owners for the relevant releases affected by this vulnerability.

The Zephyr Security Subcommittee shall review the reported vulnerabilities during any meeting with more than three people in attendance. During this review, they shall determine if new issues need to be embargoed.

The guideline for embargo will be based on: 1. Severity of the issue, and 2. Exploitability of the issue. Issues that the subcommittee decides do not need an embargo will be reproduced in the regular Zephyr project bug tracking system.

Security sensitive vulnerabilities shall be made public after an embargo period of at most 90 days. The intent is to allow 30 days within the Zephyr project to fix the issues, and 60 days for external parties building products using Zephyr to be able to apply and distribute these fixes.

Fixes to the code shall be made through pull requests PR in the Zephyr project github. Developers shall make an attempt to not reveal the sensitive nature of what is being fixed, and shall not refer to CVE numbers that have been assigned to the issue. The developer instead should merely describe what has been fixed.

The security subcommittee will maintain information mapping embargoed CVEs to these PRs (this information is within the Github security advisories), and produce regular reports of the state of security issues.

Each issue that is considered a security vulnerability shall be assigned a CVE number. As fixes are created, it may be necessary to allocate additional CVE numbers, or to retire numbers that were assigned.

Vulnerability Notification

Each Zephyr release shall contain a report of CVEs that were fixed in that release. Because of the sensitive nature of these vulnerabilities, the release shall merely include a list of CVEs that have been fixed. After the embargo period, the vulnerabilities page shall be updated to include additional details of these vulnerabilities. The vulnerability page shall give credit to the reporter(s) unless a reporter specifically requests anonymity.

The Zephyr project shall maintain a vulnerability-alerts mailing list. This list will be seeded initially with a contact from each project member. Additional parties can request to join this list by filling out the form at the Vulnerability Registry. These parties will be vetted by the project director to determine that they have a legitimate interest in knowing about security vulnerabilities during the embargo period.

Periodically, the security subcommittee will send information to this mailing list describing known embargoed issues, and their backport status within the project. This information is intended to allow them to determine if they need to backport these changes to any internal trees.

When issues have been triaged, this list will be informed of:

  • The Zephyr Project security advisory link (GitHub).

  • The CVE number assigned.

  • The subsystem involved.

  • The severity of the issue.

After acceptance of a PR fixing the issue (merged), in addition to the above, the list will be informed of:

  • The association between the CVE number and the PR fixing it.

  • Backport plans within the Zephyr project.

Backporting of Security Vulnerabilities

Each security issue fixed within zephyr shall be backported to the following releases:

  • The current Long Term Stable (LTS) release.

  • The most recent two releases.

The developer of the fix shall be responsible for any necessary backports, and apply them to any of the above listed release branches, unless the fix does not apply (the vulnerability was introduced after this release was made).

Backports will be tracked on the security advisory.

Need to Know

Due to the sensitive nature of security vulnerabilities, it is important to share details and fixes only with those parties that have a need to know. The following parties will need to know details about security vulnerabilities before the embargo period ends:

  • Maintainers will have access to all information within their domain area only.

  • The current release manager, and the release manager for historical releases affected by the vulnerability (see backporting above).

  • The Project Security Incident Response (PSIRT) team will have full access to information. The PSIRT is made up of representatives from platinum members, and volunteers who do work on triage from other members.

  • As needed, release managers and maintainers may be invited to attend additional security meetings to discuss vulnerabilities.