CVE-2026-4018
Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.
NVD · uneditedTOCTOU Race Condition in specific trace commands of the TraceEvent() system call could allow an attacker with local access and with the PROCMGR_AID_TRACE ability, to cause information disclosure, data tampering or a crash of the QNX Neutrino kernel.
Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.
dbcve analysis · moderate confidenceA Time-of-Check-Time-of-Use (TOCTOU) race condition exists in specific trace commands within the TraceEvent() system call in QNX Neutrino. An attacker with local access and the PROCMGR_AID_TRACE ability can exploit the race between checking access permissions and using the trace data, potentially causing information disclosure, data tampering, or kernel crash.
Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.
CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.
From the vector- Attack vector
- Local
- Complexity
- High
- Privileges
- High
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- High
- Availability
- High
CVSS:3.1/AV:L/AC:H/PR:H/UI:N/S:U/C:H/I:H/A:H
Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.
dbcve checksWork through these to decide whether this CVE applies to you.
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Identify the operating systemRun 'uname -a' or 'osinfo' to confirm the system is running QNX NeutrinoAffected if The system is running QNX Neutrino and the version falls within the affected range (if known)
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Determine the QNX Neutrino versionRun 'uname -r' or check '/proc/version' to obtain the kernel version for comparison against any affected version rangesAffected if The installed version matches or falls within the affected version ranges for this CVE
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Verify PROCMGR_AID_TRACE ability assignmentCheck if the PROCMGR_AID_TRACE ability is assigned to any users or processes using 'ls -la /proc/ability' or 'showability' command; also inspect any ability configuration files in /etc/ability/ or /usr/local/etc/ability/Affected if PROCMGR_AID_TRACE ability is granted to any user or process beyond the system administrator
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Identify processes using TraceEvent system callUse 'traceprt' or 'proctree' with tracing flags enabled to list processes that have invoked TraceEvent; also check for any custom trace consumers running on the systemAffected if Any user process is actively using the TraceEvent() system call with trace commands that are subject to the TOCTOU race condition
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Review trace command configurationExamine /etc/trace/* or /usr/share/trace/ directories for trace configuration files; check trace buffers and logging settings for evidence of the vulnerable trace command handlersAffected if Trace configurations include the specific trace commands affected by the race condition in TraceEvent()
A user is affected if the system runs a vulnerable version of QNX Neutrino AND has the PROCMGR_AID_TRACE ability assigned to processes that use the TraceEvent() system call with the vulnerable trace commands.
Generated from the published advisory. Verify against your own configuration.
Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.
From vendor dataRestrict assignment of the PROCMGR_AID_TRACE ability to minimize the attack surface; review and add proper synchronization to the affected trace command handlers in the TraceEvent() implementation to eliminate the race window.
- Consultation4.0 h
- Implementation16.0 h
- Testing8.0 h
- Review / QA4.0 h
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Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2026-4018 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2026-4018 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
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- Verified mitigations, workarounds, and config changes
- Version or environment caveats, and links to real fixes
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