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CVE-2026-72333
Bluetooth: L2CAP: fix tx ident leak for commands without a response
Overview
Description

In the Linux kernel, the following vulnerability has been resolved: Bluetooth: L2CAP: fix tx ident leak for commands without a response Commit 6c3ea155e5ee ("Bluetooth: L2CAP: Fix not tracking outstanding TX ident") changed ident allocation to use an IDA, releasing idents in l2cap_put_ident() when the matching response command is received. But identifiers allocated for commands that have no response defined are never released. In particular L2CAP_LE_CREDITS is sent repeatedly for the lifetime of an LE CoC channel, so a peer streaming data to the host exhausts the 1-255 ident range after 254 credit packets. From then on l2cap_get_ident() fails: kernel: Bluetooth: Unable to allocate ident: -28 and every subsequent L2CAP_LE_CREDITS packet is sent with ident 0, which is invalid (Core Spec, Vol 3, Part A, Section 4: "Signaling identifier 0x00 is an invalid identifier and shall never be used in any command"). Remote stacks that validate the ident drop these commands, never receive new credits, and the channel stalls permanently. With default socket buffers this happens after roughly 0.5 MB of received data (the exact amount depends on the socket receive buffer): < ACL Data TX: Handle 2048 flags 0x00 dlen 12 LE L2CAP: LE Flow Control Credit (0x16) ident 0 len 4 Source CID: 64 Credits: 1 Release the ident immediately after sending L2CAP_LE_CREDITS since no response will ever release it. Use a local variable instead of chan->ident so that an ident that an EXT_FLOWCTL channel may be waiting on (e.g. a pending reconfigure) is not overwritten by a credit packet. Also add the missing L2CAP_LE_CONN_RSP case to l2cap_put_ident() so idents allocated for outgoing L2CAP_LE_CONN_REQ commands are released when the response arrives.

Details
INFO

Published Date :

Aug. 15, 2026, 6:22 a.m.

Last Modified :

Aug. 17, 2026, 6:18 a.m.

Remotely Exploit :

No

Source :

416baaa9-dc9f-4396-8d5f-8c081fb06d67
Impact
Affected Products

The following products are affected by CVE-2026-72333 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.

ID Vendor Product Action
1 Linux linux_kernel
: Total Affected Vendor : 1 | Products : 1
Solution
Apply kernel updates to fix L2CAP ident leaks and prevent channel stalls.
  • Update the Linux kernel to the latest version.
  • Apply the specific commit addressing the ident leak.
  • Ensure L2CAP ident allocation and release are correct.
  • Restart affected services or reboot the system.
References
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-2026-72333.

URL Resource
https://git.kernel.org/stable/c/0c602cb8f148a36bfb39c25ade400bdadc023c4f
https://git.kernel.org/stable/c/6e1930ece855a4c256f1c7e6632d634cfb9888b5
https://git.kernel.org/stable/c/b8a32a5fc915b024c60f18d51b6cffd2bd64d4a6
https://git.kernel.org/stable/c/bd1e01170341291292fd4c46b5f6949da282ca6c
https://git.kernel.org/stable/c/d0a2b0c81f112540a337cde1c20251bf05ddf1da
CWE - Common Weakness Enumeration

While CVE identifies specific instances of vulnerabilities, CWE categorizes the common flaws or weaknesses that can lead to vulnerabilities. CVE-2026-72333 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-2026-72333 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-2026-72333 vulnerability anywhere in the article.

Results are limited to the first 20 news articles due to potential performance issues.

The following table lists the changes that have been made to the CVE-2026-72333 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.

  • CVE Modified by 416baaa9-dc9f-4396-8d5f-8c081fb06d67

    Aug. 17, 2026

    Action Type Old Value New Value
    Changed Affected [{'repo': 'https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git', 'vendor': 'Linux', 'product': 'Linux', 'versions': [{'status': 'affected', 'version': 'e86554c37d3d2b4b24608e0313f882cae28b8adb', 'lessThan': 'b8a32a5fc915b024c60f18d51b6cffd2bd64d4a6', 'versionType': 'git'}, {'status': 'affected', 'version': '9b24ad4787cad46a3917620799f8455c6533b8df', 'lessThan': 'bd1e01170341291292fd4c46b5f6949da282ca6c', 'versionType': 'git'}, {'status': 'affected', 'version': 'ea6cf86167b3972caa68972d2a1ad43ecbbb8331', 'lessThan': '0c602cb8f148a36bfb39c25ade400bdadc023c4f', 'versionType': 'git'}, {'status': 'affected', 'version': '6c3ea155e5ee3e56606233acde8309afda66d483', 'lessThan': 'd0a2b0c81f112540a337cde1c20251bf05ddf1da', 'versionType': 'git'}, {'status': 'affected', 'version': '6c3ea155e5ee3e56606233acde8309afda66d483', 'lessThan': '6e1930ece855a4c256f1c7e6632d634cfb9888b5', 'versionType': 'git'}, {'status': 'affected', 'version': 'ed97bb2cf96684ee646be6f37e4c4835f9d30caa', 'versionType': 'git'}, {'status': 'affected', 'version': '84bc3197f7d87c5b89c156e853d0561a9154eceb', 'versionType': 'git'}, {'status': 'affected', 'version': '8c1cdbc1bacc0cf9c27c3ebda11a81c3dcd01630', 'versionType': 'git'}, {'status': 'affected', 'version': '6.18.21', 'lessThan': '6.18.40', 'versionType': 'semver'}, {'status': 'affected', 'version': '5.10.261', 'lessThan': '5.11', 'versionType': 'semver'}, {'status': 'affected', 'version': '5.15.212', 'lessThan': '5.16', 'versionType': 'semver'}, {'status': 'affected', 'version': '6.19.11', 'lessThan': '6.20', 'versionType': 'semver'}], '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': '7.0'}, {'status': 'unaffected', 'version': '0', 'lessThan': '7.0', 'versionType': 'semver'}, {'status': 'unaffected', 'version': '6.18.40', 'versionType': 'semver', 'lessThanOrEqual': '6.18.*'}, {'status': 'unaffected', 'version': '7.1.5', 'versionType': 'semver', 'lessThanOrEqual': '7.1.*'}, {'status': 'unaffected', 'version': '7.2-rc3', 'versionType': 'original_commit_for_fix', 'lessThanOrEqual': '*'}], 'programFiles': ['net/bluetooth/l2cap_core.c'], 'defaultStatus': 'affected'}] [{'repo': 'https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git', 'vendor': 'Linux', 'product': 'Linux', 'versions': [{'status': 'affected', 'version': 'e86554c37d3d2b4b24608e0313f882cae28b8adb', 'lessThan': 'b8a32a5fc915b024c60f18d51b6cffd2bd64d4a6', 'versionType': 'git'}, {'status': 'affected', 'version': '9b24ad4787cad46a3917620799f8455c6533b8df', 'lessThan': 'bd1e01170341291292fd4c46b5f6949da282ca6c', 'versionType': 'git'}, {'status': 'affected', 'version': 'ea6cf86167b3972caa68972d2a1ad43ecbbb8331', 'lessThan': '0c602cb8f148a36bfb39c25ade400bdadc023c4f', 'versionType': 'git'}, {'status': 'affected', 'version': '6c3ea155e5ee3e56606233acde8309afda66d483', 'lessThan': 'd0a2b0c81f112540a337cde1c20251bf05ddf1da', 'versionType': 'git'}, {'status': 'affected', 'version': '6c3ea155e5ee3e56606233acde8309afda66d483', 'lessThan': '6e1930ece855a4c256f1c7e6632d634cfb9888b5', 'versionType': 'git'}, {'status': 'affected', 'version': 'ed97bb2cf96684ee646be6f37e4c4835f9d30caa', 'versionType': 'git'}, {'status': 'affected', 'version': '84bc3197f7d87c5b89c156e853d0561a9154eceb', 'versionType': 'git'}, {'status': 'affected', 'version': '8c1cdbc1bacc0cf9c27c3ebda11a81c3dcd01630', 'versionType': 'git'}, {'status': 'affected', 'version': '6.18.21', 'lessThan': '6.18.40', 'versionType': 'semver'}, {'status': 'affected', 'version': '5.10.261', 'lessThan': '5.11', 'versionType': 'semver'}, {'status': 'affected', 'version': '5.15.212', 'lessThan': '5.16', 'versionType': 'semver'}, {'status': 'affected', 'version': '6.19.11', 'lessThan': '6.20', 'versionType': 'semver'}], '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': '7.0'}, {'status': 'unaffected', 'version': '0', 'lessThan': '7.0', 'versionType': 'semver'}, {'status': 'unaffected', 'version': '6.18.40', 'versionType': 'semver', 'lessThanOrEqual': '6.18.*'}, {'status': 'unaffected', 'version': '7.1.5', 'versionType': 'semver', 'lessThanOrEqual': '7.1.*'}, {'status': 'unaffected', 'version': '7.2', 'versionType': 'original_commit_for_fix', 'lessThanOrEqual': '*'}], 'programFiles': ['net/bluetooth/l2cap_core.c'], 'defaultStatus': 'affected'}]
  • 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': 'e86554c37d3d2b4b24608e0313f882cae28b8adb', 'lessThan': 'b8a32a5fc915b024c60f18d51b6cffd2bd64d4a6', 'versionType': 'git'}, {'status': 'affected', 'version': '9b24ad4787cad46a3917620799f8455c6533b8df', 'lessThan': 'bd1e01170341291292fd4c46b5f6949da282ca6c', 'versionType': 'git'}, {'status': 'affected', 'version': 'ea6cf86167b3972caa68972d2a1ad43ecbbb8331', 'lessThan': '0c602cb8f148a36bfb39c25ade400bdadc023c4f', 'versionType': 'git'}, {'status': 'affected', 'version': '6c3ea155e5ee3e56606233acde8309afda66d483', 'lessThan': 'd0a2b0c81f112540a337cde1c20251bf05ddf1da', 'versionType': 'git'}, {'status': 'affected', 'version': '6c3ea155e5ee3e56606233acde8309afda66d483', 'lessThan': '6e1930ece855a4c256f1c7e6632d634cfb9888b5', 'versionType': 'git'}, {'status': 'affected', 'version': 'ed97bb2cf96684ee646be6f37e4c4835f9d30caa', 'versionType': 'git'}, {'status': 'affected', 'version': '84bc3197f7d87c5b89c156e853d0561a9154eceb', 'versionType': 'git'}, {'status': 'affected', 'version': '8c1cdbc1bacc0cf9c27c3ebda11a81c3dcd01630', 'versionType': 'git'}, {'status': 'affected', 'version': '6.18.21', 'lessThan': '6.18.40', 'versionType': 'semver'}, {'status': 'affected', 'version': '5.10.261', 'lessThan': '5.11', 'versionType': 'semver'}, {'status': 'affected', 'version': '5.15.212', 'lessThan': '5.16', 'versionType': 'semver'}, {'status': 'affected', 'version': '6.19.11', 'lessThan': '6.20', 'versionType': 'semver'}], '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': '7.0'}, {'status': 'unaffected', 'version': '0', 'lessThan': '7.0', 'versionType': 'semver'}, {'status': 'unaffected', 'version': '6.18.40', 'versionType': 'semver', 'lessThanOrEqual': '6.18.*'}, {'status': 'unaffected', 'version': '7.1.5', 'versionType': 'semver', 'lessThanOrEqual': '7.1.*'}, {'status': 'unaffected', 'version': '7.2-rc3', '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 tx ident leak for commands without a response Commit 6c3ea155e5ee ("Bluetooth: L2CAP: Fix not tracking outstanding TX ident") changed ident allocation to use an IDA, releasing idents in l2cap_put_ident() when the matching response command is received. But identifiers allocated for commands that have no response defined are never released. In particular L2CAP_LE_CREDITS is sent repeatedly for the lifetime of an LE CoC channel, so a peer streaming data to the host exhausts the 1-255 ident range after 254 credit packets. From then on l2cap_get_ident() fails: kernel: Bluetooth: Unable to allocate ident: -28 and every subsequent L2CAP_LE_CREDITS packet is sent with ident 0, which is invalid (Core Spec, Vol 3, Part A, Section 4: "Signaling identifier 0x00 is an invalid identifier and shall never be used in any command"). Remote stacks that validate the ident drop these commands, never receive new credits, and the channel stalls permanently. With default socket buffers this happens after roughly 0.5 MB of received data (the exact amount depends on the socket receive buffer): < ACL Data TX: Handle 2048 flags 0x00 dlen 12 LE L2CAP: LE Flow Control Credit (0x16) ident 0 len 4 Source CID: 64 Credits: 1 Release the ident immediately after sending L2CAP_LE_CREDITS since no response will ever release it. Use a local variable instead of chan->ident so that an ident that an EXT_FLOWCTL channel may be waiting on (e.g. a pending reconfigure) is not overwritten by a credit packet. Also add the missing L2CAP_LE_CONN_RSP case to l2cap_put_ident() so idents allocated for outgoing L2CAP_LE_CONN_REQ commands are released when the response arrives.
    Added Reference https://git.kernel.org/stable/c/0c602cb8f148a36bfb39c25ade400bdadc023c4f
    Added Reference https://git.kernel.org/stable/c/6e1930ece855a4c256f1c7e6632d634cfb9888b5
    Added Reference https://git.kernel.org/stable/c/b8a32a5fc915b024c60f18d51b6cffd2bd64d4a6
    Added Reference https://git.kernel.org/stable/c/bd1e01170341291292fd4c46b5f6949da282ca6c
    Added Reference https://git.kernel.org/stable/c/d0a2b0c81f112540a337cde1c20251bf05ddf1da
EPSS is a daily estimate of the probability of exploitation activity being observed over the next 30 days. Following chart shows the EPSS score history of the vulnerability.
CVSS
Vulnerability Scoring Details
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