CVE-2026-74540
Bluetooth: L2CAP: fix UAF in l2cap_le_connect_rsp
Description
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.
INFO
Published Date :
Aug. 15, 2026, 1:17 p.m.
Last Modified :
Aug. 15, 2026, 1:17 p.m.
Remotely Exploit :
No
Source :
416baaa9-dc9f-4396-8d5f-8c081fb06d67
Affected Products
The following products are affected by CVE-2026-74540
vulnerability.
Even if cvefeed.io is aware of the exact versions of the
products
that
are
affected, the information is not represented in the table below.
No affected product recoded yet
Solution
- Update the Linux kernel to the patched version.
- Verify the patch is applied correctly.
- Reboot the system if necessary.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-74540.
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-74540 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-74540
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-74540 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-74540 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
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New CVE Received by 416baaa9-dc9f-4396-8d5f-8c081fb06d67
Aug. 15, 2026
Action Type Old Value New Value Added Affected [{'repo': 'https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git', 'vendor': 'Linux', 'product': 'Linux', 'versions': [{'status': 'affected', 'version': 'f1496dee9cbde2a62821f4441dadb0d3360f60c3', 'lessThan': 'fd4c1e301bdec60a40728ea37de531cbccda501a', 'versionType': 'git'}, {'status': 'affected', 'version': 'f1496dee9cbde2a62821f4441dadb0d3360f60c3', 'lessThan': '522b730c62c53a1981604fd73524697fd347830d', 'versionType': 'git'}, {'status': 'affected', 'version': 'f1496dee9cbde2a62821f4441dadb0d3360f60c3', 'lessThan': '58e3c5289ad230a7e24ae4b0c7b43f5ee6e32136', 'versionType': 'git'}, {'status': 'affected', 'version': 'f1496dee9cbde2a62821f4441dadb0d3360f60c3', 'lessThan': '09f447accc2570751e7d17f0dc0788b40d3edade', 'versionType': 'git'}, {'status': 'affected', 'version': 'f1496dee9cbde2a62821f4441dadb0d3360f60c3', 'lessThan': 'c4740e7f23ff9a8210198d8b4703259e21b9f69d', 'versionType': 'git'}], 'programFiles': ['net/bluetooth/l2cap_core.c'], 'defaultStatus': 'unaffected'}, {'repo': 'https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git', 'vendor': 'Linux', 'product': 'Linux', 'versions': [{'status': 'affected', 'version': '3.14'}, {'status': 'unaffected', 'version': '0', 'lessThan': '3.14', 'versionType': 'semver'}, {'status': 'unaffected', 'version': '6.6.151', 'versionType': 'semver', 'lessThanOrEqual': '6.6.*'}, {'status': 'unaffected', 'version': '6.12.103', 'versionType': 'semver', 'lessThanOrEqual': '6.12.*'}, {'status': 'unaffected', 'version': '6.18.44', 'versionType': 'semver', 'lessThanOrEqual': '6.18.*'}, {'status': 'unaffected', 'version': '7.1.8', 'versionType': 'semver', 'lessThanOrEqual': '7.1.*'}, {'status': 'unaffected', 'version': '7.2-rc6', 'versionType': 'original_commit_for_fix', 'lessThanOrEqual': '*'}], 'programFiles': ['net/bluetooth/l2cap_core.c'], 'defaultStatus': 'affected'}] Added Description 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. Added Reference https://git.kernel.org/stable/c/09f447accc2570751e7d17f0dc0788b40d3edade Added Reference https://git.kernel.org/stable/c/522b730c62c53a1981604fd73524697fd347830d Added Reference https://git.kernel.org/stable/c/58e3c5289ad230a7e24ae4b0c7b43f5ee6e32136 Added Reference https://git.kernel.org/stable/c/c4740e7f23ff9a8210198d8b4703259e21b9f69d Added Reference https://git.kernel.org/stable/c/fd4c1e301bdec60a40728ea37de531cbccda501a