CVE-2026-98733: Linux kernel · Bluetooth: hci_core: Serialize fragmented ISO packet queueing
Affects Linux kernelSource GCVE Database
Not known to be exploited · CVSS 7.3 High.
Data as of 28 Oct 2026, 01:28 UTC
CVSS:4.0/AV:L/AC:L/AT:P/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:NExploitation evidence
Disclosed: evidence found.
CVE published 18 Oct 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.
What to do
Affected software
| Product | Affected | Fixed in |
|---|---|---|
Ubuntu 26.04 LTSlinuxpkg:deb/ubuntu/linux?arch=source&distro=resoluteOther threats | Affected
| Fixed in– |
Ubuntu 26.04 LTSlinux-awspkg:deb/ubuntu/linux-aws?arch=source&distro=resoluteOther threats | Affected
| Fixed in– |
Ubuntu 26.04 LTSlinux-azurepkg:deb/ubuntu/linux-azure?arch=source&distro=resoluteOther threats | Affected
| Fixed in– |
Ubuntu 26.04 LTSlinux-azure-fdepkg:deb/ubuntu/linux-azure-fde?arch=source&distro=resoluteOther threats | Affected
| Fixed in– |
Ubuntu 26.04 LTSlinux-gcppkg:deb/ubuntu/linux-gcp?arch=source&distro=resoluteOther threats | Affected
| Fixed in– |
Ubuntu 26.04 LTSlinux-gkepkg:deb/ubuntu/linux-gke?arch=source&distro=resoluteOther threats | Affected
| Fixed in– |
Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.
Description
In the Linux kernel, the following vulnerability has been resolved: Bluetooth: hci_core: Serialize fragmented ISO packet queueing The fragmented path in hci_queue_iso() calls __skb_queue_tail() without holding conn->data_q.lock. The socket lock serializes senders, but the transmit worker can concurrently remove packets from this queue using skb_dequeue(). After an insertion saves the old tail pointer, hci_sched_iso() can dequeue that packet and pass it to the driver. The driver can free the packet before the insertion resumes and writes to the old tail's next pointer, causing a use-after-free. Concurrent updates can also corrupt the queue. KASAN reported: BUG: KASAN: slab-use-after-free in hci_send_iso+0xc7d/0xe10 Call Trace: hci_send_iso+0xc7d/0xe10 iso_sock_sendmsg+0x710/0x900 __sys_sendto+0x34a/0x3a0 Allocated by task 86: __alloc_skb+0xdd/0x820 alloc_skb_with_frags+0x7e/0x770 sock_alloc_send_pskb+0x67a/0x820 bt_skb_sendmsg.constprop.0+0xc0/0x6c0 iso_sock_sendmsg+0x44e/0x900 Freed by task 90: kmem_cache_free+0xcb/0x3d0 vhci_read+0x33f/0x4d0 vfs_read+0x177/0xa20 Hold the queue lock across the entire fragment batch, as hci_queue_acl() does, to serialize insertion against dequeue while preserving fragment ordering.
References
- ubuntu.com/security/CVE-2026-98733 (opens in a new tab)
- cve.org/CVERecord?id=CVE-2026-98733 (opens in a new tab)
- git.kernel.org/stable/c/d6d709981208567868c5c01ebd1bec5e5e7fdab0 (opens in a new tab)
- git.kernel.org/stable/c/1a572db43c057566771b485598ad2e66cb390821 (opens in a new tab)
- git.kernel.org/stable/c/708cdd203d0bbcf9255fffb2e4c308d5b28851a7 (opens in a new tab)
- git.kernel.org/stable/c/a7161730a3ab3f0a3896000db7ab0284683936e6 (opens in a new tab)