CVE-2026-90255 — Kernel
HIGHCVE-2026-90255 is a high-severity (CVSS 8.8) vulnerability in Kernel. A fix is available for Kernel — see the affected versions and patch details below.
Bluetooth: hci_conn: fix the SCO setup context lifetime
EPSS Exploitation Probability
EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.
How urgent is this, really
CVE-2026-90255 plotted by exploitation likelihood (EPSS) against impact (CVSS). The shaded corner — EPSS 50%+ and CVSS 7.0+ — is where this CVE doesn't sit, though severity or exploitability alone can still warrant action.
Where this sits among everything scored
Of 376,715 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Real counts from FIRST.org, not a sample — log-scaled since the landscape is heavily right-skewed.
Real-World Exposure
KernelReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects Linux packages — download data is not available via public APIs for these ecosystems.
Description
In the Linux kernel, the following vulnerability has been resolved:
Bluetooth: hci_conn: fix the SCO setup context lifetime
hci_setup_sync() queues a conn_handle_t with a NULL destroy callback, so the context is only freed if hci_enhanced_setup_sync() actually runs. An entry that is cancelled instead is leaked, as _hci_cmd_sync_cancel_entry() does not release entry->data when there is no destroy callback, and hci_cmd_sync_clear() cancels every pending entry when the controller is unregistered.
The context also stores a bare hci_conn pointer, so the connection can be freed while the work is queued. The dequeue in hci_conn_del() does not cover it either, as it matches on entry->data == conn and entry->data is the wrapper here. Same problem as commit 2f5d635ad590 ("Bluetooth: hci_sync: hold conn in hci_connect_acl/le_sync() callbacks").
Hold the connection and release both from a destroy callback. The submission failure path drops both, since hci_cmd_sync_submit() does not call the destroy callback when it fails to queue.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐧Linux | Kernel | ≥ 6.1.0&&< 6.1.188 | 6.1.188 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for Kernel, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update Kernel to 6.1.188 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-90255 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like CVE-2026-90255 can be triaged on real exposure rather than presence alone.
Tailored to CVE-2026-90255. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is CVE-2026-90255 in your dependencies?
O3 Security finds CVE-2026-90255 across Linux dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.