Bluetooth: L2CAP: fix UAF in l2cap_le_connect_rsp
Key facts
- Attack vector
- Adjacent network
- Privileges required
- None
- User interaction
- None
- Attack complexity
- Low
- Impact type
- —
- Confidentiality · integrity · availability
- High · High · High
- Fix status
- Partial Red Hat: 3 without a fix
Attack profile from CVSS 3.1 · CNA. Fix status from CNA and Red Hat.
Summary
In the Linux kernel, the following vulnerability has been resolved: Bluetooth: L2CAP: fix UAF in l2cap_le_connect_rsp l2cap_le_connect_rsp() obtains a channel via __l2cap_get_chan_by_ident() but neither holds a reference nor uses l2cap_chan_hold_unless_zero() before locking and operating on it. A concurrent l2cap_chan_del() triggered by a remote disconnect can free the channel between the lookup and l2cap_chan_lock(), causing a use-after-free. The BR/EDR counterpart l2cap_connect_rsp() and the sibling handler l2cap_le_command_rej() already use l2cap_chan_hold_unless_zero() to safely hold a reference, but l2cap_le_connect_rsp() was left unprotected. Fix by adding l2cap_chan_hold_unless_zero() after the ident lookup and l2cap_chan_put() on the exit path, consistent with other L2CAP response handlers.
Why it matters now
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- None
- Automatable
- No
- Technical impact
- Total
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
Remediation
- Fix · CNA Linux (Linux) Fixed in 5.10.265, 5.15.216, 6.1.183, 6.6.151, 6.12.103, 6.18.44, 7.1.8, 7.2
Vendor assessments
Red Hat
Red Hat rating: Moderate. Red Hat's page for this CVE →
| Product | Status | Plan or fix |
|---|---|---|
| Red Hat Enterprise Linux 10 | Affected | No fix yet: Fix deferred |
| Red Hat Enterprise Linux 8 | Affected | No fix yet: Fix deferred |
| Red Hat Enterprise Linux 9 | Affected | No fix yet: Fix deferred |
Not affected: 2 products
- Red Hat Enterprise Linux 6
- Red Hat Enterprise Linux 7
Timeline
- 2026-10-02 Threatist record created from CVE-2026-74540
- 2026-10-03 Alias added: GHSA-j62w-h52r-54ch
- 2026-10-18 CISA SSVC decision points changed
- 2026-10-18 Priority changed: LOW → MEDIUM
References
Other 8
- https://git.kernel.org/stable/c/15d6c2367217a6a20b1abae9f38ded716bf620f1
- https://git.kernel.org/stable/c/1818180fe12d6cec7a437bc59cde8efdf6b10250
- https://git.kernel.org/stable/c/8325eafb38c3dee5af329266393763693d17381b
- https://git.kernel.org/stable/c/fd4c1e301bdec60a40728ea37de531cbccda501a
- https://git.kernel.org/stable/c/522b730c62c53a1981604fd73524697fd347830d
- https://git.kernel.org/stable/c/58e3c5289ad230a7e24ae4b0c7b43f5ee6e32136
- https://git.kernel.org/stable/c/09f447accc2570751e7d17f0dc0788b40d3edade
- https://git.kernel.org/stable/c/c4740e7f23ff9a8210198d8b4703259e21b9f69d
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Sources
- CVE-2026-74540 · CVE Program
- CVE-2026-74540 · NVD
- FIRST EPSS
- GHSA-j62w-h52r-54ch · GitHub Advisory Database · CC BY 4.0
- CVE-2026-74540 · Red Hat security data · CC BY 4.0
This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences