CVE-2026-46275 — Bluetooth: hci_uart: fix UAFs and race conditions in close and init paths
In the Linux kernel, the following vulnerability has been resolved: Bluetooth: hci_uart: fix UAFs and race conditions in close and init paths Vulnerabilities leading to Use-After-Free (UAF) and Null Pointer Dereference (NPD) conditions were observed in the lifecycle management of hci_uart. The primary issue arises because the workqueues (init_ready and write_work) are only flushed/cancelled if the HCI_UART_PROTO_READY flag is set during TTY close. If a hangup occurs before setup completes, hci_uart_tty_close() skips the teardown of these workqueues and proceeds to free the `hu` struct. When the scheduled work executes later, it blindly dereferences the freed `hu` struct. Furthermore, several data races and UAFs were identified in the teardown sequence: 1. Calling hci_uart_flush() from hci_uart_close() without effectively disabling write_work causes a race condition where both can concurrently double-free hu->tx_skb. This happens because protocol timers can concurrently invoke hci_uart_tx_wakeup() and requeue write_work. 2. Calling hci_free_dev(hdev) before hu->proto->close(hu) causes a UAF when vendor specific protocol close callbacks dereference hu->hdev. 3. In the initialization error paths, failing to take the proto_lock write lock before clearing PROTO_READY leads to races with active readers. Additionally, hci_uart_tty_receive() accesses hu->hdev outside the read lock, leading to UAFs if the initialization error path frees hdev concurrently. Fix these synchronization and lifecycle issues by: 1. Re-ordering hci_uart_tty_close() to clear HCI_UART_PROTO_READY first, followed immediately by a cancel_work_sync(&hu->write_work). Clearing the flag locks out concurrent protocol timers from successfully invoking hci_uart_tx_wakeup(), effectively rendering the cancellation permanent and preventing the tx_skb double-free. 2. Note: Clearing PROTO_READY early causes hci_uart_close() to skip hu->proto->flush(). This is perfectly safe in the tty_close path because hu->proto->close() executes shortly after, which intrinsically purges all protocol SKB queues and tears down the state. 3. Relocating hu->proto->close(hu) strictly prior to hci_free_dev(hdev) across all close and error paths to prevent vendor-level UAFs. 4. Moving the hdev->stat.byte_rx increment in hci_uart_tty_receive() inside the proto_lock read-side critical section to safely synchronize with device unregistration. 5. Adding cancel_work_sync(&hu->write_work) to hci_uart_close() to safely flush the workqueue before hci_uart_flush() is invoked via the HCI core. 6. Utilizing cancel_work_sync() instead of disable_work_sync() across all paths to prevent permanently breaking user-space retry capabilities.
Who exploits it and how urgent it is
A 0–100 score combining confirmed exploitation, ransomware and APT use, public exploits, EPSS and severity.
How the score was calculated
- EPSS 0.2% (30-day exploitation probability)+1
- Technical severity (high)+6
The score orders the patch queue; it does not replace your asset context (internet exposure, criticality, compensating controls).
Triage
Is it exploited, how likely is exploitation, what does it touch, and how severe do the sources call it.
Remediation
Fixes and mitigations documented by the sources — linked to the original advisory.
- Documented patch — git.kernel.org (NIST National Vulnerability Database)
- Documented patch — git.kernel.org (NIST National Vulnerability Database)
- Documented patch — git.kernel.org (NIST National Vulnerability Database)
- Documented patch — git.kernel.org (NIST National Vulnerability Database)
- Documented patch — git.kernel.org (NIST National Vulnerability Database)
- Documented patch — git.kernel.org (NIST National Vulnerability Database)
- Documented patch — git.kernel.org (NIST National Vulnerability Database)
- Documented patch — git.kernel.org (NIST National Vulnerability Database)
First 24 hours
Ordered from the record’s own fields — exposure first, because you cannot patch what you have not found. A rule-generated starting point.
- Identify exposed assets running the affected vendor/product/version combinations (Linux Linux, Linux Linux Kernel).
- Apply the fixed version or the patch documented under Remediation.
- Search available logs for exploit probes matching the vulnerability class (logic error), errors and authentication anomalies.
Affected scope
Vendor, product and versions as the sources word them.
| Vendor | Product | Versions | Status | Source |
|---|---|---|---|---|
| Linux | Linux |
version 3fe978892ab46efc2f3830d9abc015eff72caaf9≥ 3b799254cf6f481460719023d7a18f46651e5e7f and < 9d20d48be2c4a071fb015eb09bda2cecd25daf34≥ 3b799254cf6f481460719023d7a18f46651e5e7f and < 81c7a3c22a0f2808cf4ae0b4908f59763b23606d≥ 3b799254cf6f481460719023d7a18f46651e5e7f and < 192cb0f1ca706d9a1bc36ae0ad5f666d1e4fd894≥ 3b799254cf6f481460719023d7a18f46651e5e7f and < 7338031946bd06f6dff149e67b60c4cd083bfea8≥ 3b799254cf6f481460719023d7a18f46651e5e7f and < c1bb9336ae6b54a5f6a353c4bd4ed9a4307e429bversion cd27019bc149f20f12ebec943c2b4c775745a5a0version aea63181b6fcb6b9ccde1ada9ea51be19c4015af and 11 moreversion 0d234d1135dcd8876de0576dac68efd0a87eef87≥ 3b799254cf6f481460719023d7a18f46651e5e7f and < c85cff648a2bc92322912db5f1727ad05afae7b6version 0d987e14bebaf0f67ee7dbefaf6165c62cd1d27f≥ 4.14.203 and < 4.15≥ 4.19.153 and < 4.20≥ 5.4.73 and < 5.5≥ 5.8.17 and < 5.9≥ 5.9.2 and < 5.10version 5.10≥ 3b799254cf6f481460719023d7a18f46651e5e7f and < e2d19969c8d9198ecc3090bcd5312ecd503a3339≥ 3b799254cf6f481460719023d7a18f46651e5e7f and < 78aad93e938f013d9272fe0ee168f27883afa95c |
Vulnerable | CVE Program (cve.org) e CISA ADP |
| Linux | Linux Kernel |
≥ 4.19.153 and < 4.20≥ 4.14.203 and < 4.15≥ 5.4.73 and < 5.5≥ 5.8.17 and < 5.9≥ 5.9.2 and < 5.10.258≥ 5.11 and < 5.15.209≥ 5.16 and < 6.1.175≥ 6.2 and < 6.6.142 and 7 more≥ 6.7 and < 6.12.92≥ 6.13 and < 6.18.34≥ 6.19 and < 7.0.11version 7.1-rc1version 7.1-rc2version 7.1-rc3version 7.1-rc4 |
Vulnerable | NIST National Vulnerability Database |
Attack characteristics
The CVSS vector, decoded. It describes the attack, not your exposure to it.
Every base score collected
Sources score independently and may disagree; each row says who scored it and under which version.
| Score | Version | Severity | Expl. | Impact | Scored by |
|---|---|---|---|---|---|
| 7.8 | CVSS 3.1 | High | 1.8 | 5.9 | 416baaa9-dc9f-4396-8d5f-8c081fb06d67 via NIST National Vulnerability Database |
| 7.8 | CVSS 3.1 | High | — | — | GitHub, Inc. via GitHub Security Advisories |
| 7.8 | CVSS 3.1 | High | — | — | Linux via CVE Program (cve.org) e CISA ADP |
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H (score shown at the top: 416baaa9-dc9f-4396-8d5f-8c081fb06d67) Weakness MITRE
Weakness class according to MITRE’s CWE catalog.
EPSS over time FIRST
Oct 13, 2026 → Oct 14, 2026 · 2 reading(s) · max 0.19%
Detection
Read off the CVSS vector and the weakness class. Starting points, not tested rules.
- Local/physical vector: focus on endpoint telemetry (EDR) from affected hosts.
Timeline
What happened to this CVE, newest first.
- 2026
- Source status changed · Analyzed → Modified
- Affected products added · linux/linux
- Record published
- Fix documented
- CVSS changed · 7.8
- Source status changed · → Analyzed
- Record created in this database
- CVE published
Source activity
Repeated readings are counted rather than listed.
- 2× References added · Oct 14, 2026 – Oct 15, 2026
- 1× Official description updated · Oct 13, 2026 – Oct 13, 2026
References
11 on the record
- git.kernel.org/stable/c/78aad93e938f013d9272fe0ee168f27883afa95c
- git.kernel.org/stable/c/e2d19969c8d9198ecc3090bcd5312ecd503a3339
- git.kernel.org/stable/c/c1bb9336ae6b54a5f6a353c4bd4ed9a4307e429b
- git.kernel.org/stable/c/c85cff648a2bc92322912db5f1727ad05afae7b6
- git.kernel.org/stable/c/81c7a3c22a0f2808cf4ae0b4908f59763b23606d
- git.kernel.org/stable/c/192cb0f1ca706d9a1bc36ae0ad5f666d1e4fd894
- git.kernel.org/stable/c/7338031946bd06f6dff149e67b60c4cd083bfea8
- git.kernel.org/stable/c/9d20d48be2c4a071fb015eb09bda2cecd25daf34
- cert-portal.siemens.com/productcert/html/ssa-784472.html
- nvd.nist.gov/vuln/detail/CVE-2026-46275
- github.com/advisories/GHSA-mpvf-w98g-3c74
Elsewhere on this site
Related CVEs (same products)
- Critical CVE-2026-99999 ipv4: validate checksum_start before completing checksum 14h
- Unknown CVE-2026-98432 ipv4: free inet_opt and ireq_opt after an RCU grace period 14h
- Unknown CVE-2026-98424 wifi: cfg80211: undo netns switch if renaming the wiphy fails 1d
- Unknown CVE-2026-98425 wifi: mac80211: don't warn when an IBSS has no channel to scan 1d
- Unknown CVE-2026-98426 wifi: mwifiex: fix IRQ leak using wrong index in MSI-X error path 1d
- Unknown CVE-2026-98427 net/sched: codel: bound the dropping loop per dequeue call 1d
Not in any source we poll
Listed rather than left blank: an empty field and an unmeasured one look identical on screen, and only one is a reason to look elsewhere.
- No CISA SSVC assessment.
- No confirmed IOCs, IP addresses, domains, file hashes, or malware artifacts supplied.
- No organization-specific asset inventory, compensating-control status, or patch deployment evidence supplied.
- No exploit packet captures, log samples, or incident case IDs supplied.
Answered from this record
Text assembled only from the fields above — no additional claims.
What should defenders know first?
CVE-2026-46275 is "Bluetooth: hci_uart: fix UAFs and race conditions in close and init paths", rated High. It affects Linux (Linux); versions are in the scope table. It is not in CISA KEV, which does not rule out exploitation. CVSS 7.8 describes technical severity. EPSS 0.19% estimates the probability of exploitation in 30 days; neither replaces your asset context. First verify whether exposed or business-critical assets run the affected versions, apply vendor fixes or mitigations, and preserve logs for review.
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