5.5
MEDIUM CVSS 3.1
CVE-2026-53208
Bluetooth: L2CAP: reject BR/EDR signaling packets over MTUsig
Description

In the Linux kernel, the following vulnerability has been resolved: Bluetooth: L2CAP: reject BR/EDR signaling packets over MTUsig net/bluetooth/l2cap_core.c:l2cap_sig_channel() accepts BR/EDR signaling packets up to the channel MTU and dispatches each command without enforcing the signaling MTU (MTUsig). A Bluetooth BR/EDR peer within radio range can send a fixed-channel CID 0x0001 packet that is larger than MTUsig and contains many L2CAP_ECHO_REQ commands before pairing. In a real-radio stock-kernel run, one 681-byte signaling packet containing 168 zero-length ECHO_REQ commands made the target transmit 168 ECHO_RSP frames over about 220 ms. Impact: a Bluetooth BR/EDR peer within radio range, before pairing, can force 168 ECHO_RSP frames from one 681-byte fixed-channel signaling packet containing packed ECHO_REQ commands. Define Linux's BR/EDR signaling MTU as the spec minimum of 48 bytes and reject any larger signaling packet with one L2CAP_COMMAND_REJECT_RSP carrying L2CAP_REJ_MTU_EXCEEDED before any command is dispatched. The Bluetooth Core spec wording for MTUExceeded says the reject identifier shall match the first request command in the packet, and that packets containing only responses shall be silently discarded. Linux intentionally deviates from that prescription: silently discarding desynchronizes the peer because the remote stack never learns its responses were dropped, and locating the first request command requires walking command headers past MTUsig, i.e. processing bytes from a packet we have already decided is too large to process. We therefore always emit one reject and use the identifier from the first command header, a single fixed-offset byte read. The unrestricted BR/EDR signaling parser and ECHO_REQ response path both trace to the initial git import; no later introducing commit is available for a Fixes tag.

INFO

Published Date :

June 25, 2026, 9:16 a.m.

Last Modified :

July 2, 2026, 8:55 p.m.

Remotely Exploit :

No

Source :

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

The following products are affected by CVE-2026-53208 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
CVSS Scores
The Common Vulnerability Scoring System is a standardized framework for assessing the severity of vulnerabilities in software and systems. We collect and displays CVSS scores from various sources for each CVE.
Score Version Severity Vector Exploitability Score Impact Score Source
CVSS 3.1 MEDIUM [email protected]
Solution
Limit L2CAP signaling packets to the specified MTU to prevent resource exhaustion.
  • Update the Linux kernel to the latest version.
  • Configure Bluetooth signaling MTU to 48 bytes.
  • Reject signaling packets exceeding the MTU.
  • Apply security patches for Bluetooth.
CWE - Common Weakness Enumeration

While CVE identifies specific instances of vulnerabilities, CWE categorizes the common flaws or weaknesses that can lead to vulnerabilities. CVE-2026-53208 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-2026-53208 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-2026-53208 vulnerability anywhere in the article.

The following table lists the changes that have been made to the CVE-2026-53208 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.

  • Initial Analysis by [email protected]

    Jul. 02, 2026

    Action Type Old Value New Value
    Added CVSS V3.1 AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
    Added CWE NVD-CWE-noinfo
    Added CPE Configuration OR *cpe:2.3:o:linux:linux_kernel:2.6.12:rc4:*:*:*:*:*:* *cpe:2.3:o:linux:linux_kernel:2.6.12:rc5:*:*:*:*:*:* *cpe:2.3:o:linux:linux_kernel:2.6.12:rc2:*:*:*:*:*:* *cpe:2.3:o:linux:linux_kernel:2.6.12:rc3:*:*:*:*:*:* *cpe:2.3:o:linux:linux_kernel:2.6.12:-:*:*:*:*:*:* *cpe:2.3:o:linux:linux_kernel:7.1:rc1:*:*:*:*:*:* *cpe:2.3:o:linux:linux_kernel:7.1:rc2:*:*:*:*:*:* *cpe:2.3:o:linux:linux_kernel:7.1:rc3:*:*:*:*:*:* *cpe:2.3:o:linux:linux_kernel:7.1:rc4:*:*:*:*:*:* *cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* versions from (including) 5.16 up to (excluding) 6.1.176 *cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* versions from (including) 6.2 up to (excluding) 6.6.143 *cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* versions from (including) 5.11 up to (excluding) 5.15.210 *cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* versions from (including) 6.13 up to (excluding) 6.18.36 *cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* versions from (including) 6.7 up to (excluding) 6.12.94 *cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* versions from (including) 6.19 up to (excluding) 7.0.13 *cpe:2.3:o:linux:linux_kernel:7.1:rc5:*:*:*:*:*:* *cpe:2.3:o:linux:linux_kernel:7.1:rc6:*:*:*:*:*:* *cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* versions from (including) 2.6.12.1 up to (excluding) 5.10.259
    Added Reference Type kernel.org: https://git.kernel.org/stable/c/214a2042b16b3c8d798a8b9ef9f36094f13a9859 Types: Patch
    Added Reference Type kernel.org: https://git.kernel.org/stable/c/a8335f3db15bd1e0e82e0db5d488fabc7d10d1ab Types: Patch
    Added Reference Type kernel.org: https://git.kernel.org/stable/c/b20e8a98dd29b121f58fcdf51e8576119aba536a Types: Patch
    Added Reference Type kernel.org: https://git.kernel.org/stable/c/dd214733544427587a95f66dbf3adff072568990 Types: Patch
    Added Reference Type kernel.org: https://git.kernel.org/stable/c/dedc92b96dc1d8919a3bdf2495ede68922ef7ebc Types: Patch
    Added Reference Type kernel.org: https://git.kernel.org/stable/c/e05c4ac575b457978a7ef441053394169084869c Types: Patch
    Added Reference Type kernel.org: https://git.kernel.org/stable/c/e2b8acf9405bd9b1baf1c54dc897b0905db689bf Types: Patch
    Added Reference Type kernel.org: https://git.kernel.org/stable/c/fa5823126239b3e453fac1a2fe50726c7f4a55e1 Types: Patch
  • CVE Modified by 416baaa9-dc9f-4396-8d5f-8c081fb06d67

    Jun. 29, 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': '1da177e4c3f41524e886b7f1b8a0c1fc7321cac2', 'lessThan': 'e05c4ac575b457978a7ef441053394169084869c', 'versionType': 'git'}, {'status': 'affected', 'version': '1da177e4c3f41524e886b7f1b8a0c1fc7321cac2', 'lessThan': 'fa5823126239b3e453fac1a2fe50726c7f4a55e1', 'versionType': 'git'}, {'status': 'affected', 'version': '1da177e4c3f41524e886b7f1b8a0c1fc7321cac2', 'lessThan': 'b20e8a98dd29b121f58fcdf51e8576119aba536a', 'versionType': 'git'}, {'status': 'affected', 'version': '1da177e4c3f41524e886b7f1b8a0c1fc7321cac2', 'lessThan': '214a2042b16b3c8d798a8b9ef9f36094f13a9859', 'versionType': 'git'}, {'status': 'affected', 'version': '1da177e4c3f41524e886b7f1b8a0c1fc7321cac2', 'lessThan': 'a8335f3db15bd1e0e82e0db5d488fabc7d10d1ab', 'versionType': 'git'}, {'status': 'affected', 'version': '1da177e4c3f41524e886b7f1b8a0c1fc7321cac2', 'lessThan': 'dedc92b96dc1d8919a3bdf2495ede68922ef7ebc', 'versionType': 'git'}, {'status': 'affected', 'version': '1da177e4c3f41524e886b7f1b8a0c1fc7321cac2', 'lessThan': 'e2b8acf9405bd9b1baf1c54dc897b0905db689bf', 'versionType': 'git'}, {'status': 'affected', 'version': '1da177e4c3f41524e886b7f1b8a0c1fc7321cac2', 'lessThan': 'dd214733544427587a95f66dbf3adff072568990', 'versionType': 'git'}, {'status': 'affected', 'version': '0', 'lessThan': '5.10.259', 'versionType': 'semver'}, {'status': 'affected', 'version': '0', 'lessThan': '5.15.210', 'versionType': 'semver'}, {'status': 'affected', 'version': '0', 'lessThan': '6.1.176', 'versionType': 'semver'}, {'status': 'affected', 'version': '0', 'lessThan': '6.6.143', 'versionType': 'semver'}, {'status': 'affected', 'version': '0', 'lessThan': '6.12.94', 'versionType': 'semver'}, {'status': 'affected', 'version': '0', 'lessThan': '6.18.36', 'versionType': 'semver'}, {'status': 'affected', 'version': '0', 'lessThan': '7.0.13', 'versionType': 'semver'}], 'programFiles': ['include/net/bluetooth/l2cap.h', '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': 'unaffected', 'version': '5.10.259', 'versionType': 'semver', 'lessThanOrEqual': '5.10.*'}, {'status': 'unaffected', 'version': '5.15.210', 'versionType': 'semver', 'lessThanOrEqual': '5.15.*'}, {'status': 'unaffected', 'version': '6.1.176', 'versionType': 'semver', 'lessThanOrEqual': '6.1.*'}, {'status': 'unaffected', 'version': '6.6.143', 'versionType': 'semver', 'lessThanOrEqual': '6.6.*'}, {'status': 'unaffected', 'version': '6.12.94', 'versionType': 'semver', 'lessThanOrEqual': '6.12.*'}, {'status': 'unaffected', 'version': '6.18.36', 'versionType': 'semver', 'lessThanOrEqual': '6.18.*'}, {'status': 'unaffected', 'version': '7.0.13', 'versionType': 'semver', 'lessThanOrEqual': '7.0.*'}, {'status': 'unaffected', 'version': '7.1', 'versionType': 'original_commit_for_fix', 'lessThanOrEqual': '*'}], 'programFiles': ['include/net/bluetooth/l2cap.h', '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': '1da177e4c3f41524e886b7f1b8a0c1fc7321cac2', 'lessThan': 'e05c4ac575b457978a7ef441053394169084869c', 'versionType': 'git'}, {'status': 'affected', 'version': '1da177e4c3f41524e886b7f1b8a0c1fc7321cac2', 'lessThan': 'fa5823126239b3e453fac1a2fe50726c7f4a55e1', 'versionType': 'git'}, {'status': 'affected', 'version': '1da177e4c3f41524e886b7f1b8a0c1fc7321cac2', 'lessThan': 'b20e8a98dd29b121f58fcdf51e8576119aba536a', 'versionType': 'git'}, {'status': 'affected', 'version': '1da177e4c3f41524e886b7f1b8a0c1fc7321cac2', 'lessThan': '214a2042b16b3c8d798a8b9ef9f36094f13a9859', 'versionType': 'git'}, {'status': 'affected', 'version': '1da177e4c3f41524e886b7f1b8a0c1fc7321cac2', 'lessThan': 'a8335f3db15bd1e0e82e0db5d488fabc7d10d1ab', 'versionType': 'git'}, {'status': 'affected', 'version': '1da177e4c3f41524e886b7f1b8a0c1fc7321cac2', 'lessThan': 'dedc92b96dc1d8919a3bdf2495ede68922ef7ebc', 'versionType': 'git'}, {'status': 'affected', 'version': '1da177e4c3f41524e886b7f1b8a0c1fc7321cac2', 'lessThan': 'e2b8acf9405bd9b1baf1c54dc897b0905db689bf', 'versionType': 'git'}, {'status': 'affected', 'version': '1da177e4c3f41524e886b7f1b8a0c1fc7321cac2', 'lessThan': 'dd214733544427587a95f66dbf3adff072568990', 'versionType': 'git'}], 'programFiles': ['include/net/bluetooth/l2cap.h', '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': '2.6.12'}, {'status': 'unaffected', 'version': '0', 'lessThan': '2.6.12', 'versionType': 'semver'}, {'status': 'unaffected', 'version': '5.10.259', 'versionType': 'semver', 'lessThanOrEqual': '5.10.*'}, {'status': 'unaffected', 'version': '5.15.210', 'versionType': 'semver', 'lessThanOrEqual': '5.15.*'}, {'status': 'unaffected', 'version': '6.1.176', 'versionType': 'semver', 'lessThanOrEqual': '6.1.*'}, {'status': 'unaffected', 'version': '6.6.143', 'versionType': 'semver', 'lessThanOrEqual': '6.6.*'}, {'status': 'unaffected', 'version': '6.12.94', 'versionType': 'semver', 'lessThanOrEqual': '6.12.*'}, {'status': 'unaffected', 'version': '6.18.36', 'versionType': 'semver', 'lessThanOrEqual': '6.18.*'}, {'status': 'unaffected', 'version': '7.0.13', 'versionType': 'semver', 'lessThanOrEqual': '7.0.*'}, {'status': 'unaffected', 'version': '7.1', 'versionType': 'original_commit_for_fix', 'lessThanOrEqual': '*'}], 'programFiles': ['include/net/bluetooth/l2cap.h', 'net/bluetooth/l2cap_core.c'], 'defaultStatus': 'affected'}]
  • New CVE Received by 416baaa9-dc9f-4396-8d5f-8c081fb06d67

    Jun. 25, 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': '1da177e4c3f41524e886b7f1b8a0c1fc7321cac2', 'lessThan': 'e05c4ac575b457978a7ef441053394169084869c', 'versionType': 'git'}, {'status': 'affected', 'version': '1da177e4c3f41524e886b7f1b8a0c1fc7321cac2', 'lessThan': 'fa5823126239b3e453fac1a2fe50726c7f4a55e1', 'versionType': 'git'}, {'status': 'affected', 'version': '1da177e4c3f41524e886b7f1b8a0c1fc7321cac2', 'lessThan': 'b20e8a98dd29b121f58fcdf51e8576119aba536a', 'versionType': 'git'}, {'status': 'affected', 'version': '1da177e4c3f41524e886b7f1b8a0c1fc7321cac2', 'lessThan': '214a2042b16b3c8d798a8b9ef9f36094f13a9859', 'versionType': 'git'}, {'status': 'affected', 'version': '1da177e4c3f41524e886b7f1b8a0c1fc7321cac2', 'lessThan': 'a8335f3db15bd1e0e82e0db5d488fabc7d10d1ab', 'versionType': 'git'}, {'status': 'affected', 'version': '1da177e4c3f41524e886b7f1b8a0c1fc7321cac2', 'lessThan': 'dedc92b96dc1d8919a3bdf2495ede68922ef7ebc', 'versionType': 'git'}, {'status': 'affected', 'version': '1da177e4c3f41524e886b7f1b8a0c1fc7321cac2', 'lessThan': 'e2b8acf9405bd9b1baf1c54dc897b0905db689bf', 'versionType': 'git'}, {'status': 'affected', 'version': '1da177e4c3f41524e886b7f1b8a0c1fc7321cac2', 'lessThan': 'dd214733544427587a95f66dbf3adff072568990', 'versionType': 'git'}, {'status': 'affected', 'version': '0', 'lessThan': '5.10.259', 'versionType': 'semver'}, {'status': 'affected', 'version': '0', 'lessThan': '5.15.210', 'versionType': 'semver'}, {'status': 'affected', 'version': '0', 'lessThan': '6.1.176', 'versionType': 'semver'}, {'status': 'affected', 'version': '0', 'lessThan': '6.6.143', 'versionType': 'semver'}, {'status': 'affected', 'version': '0', 'lessThan': '6.12.94', 'versionType': 'semver'}, {'status': 'affected', 'version': '0', 'lessThan': '6.18.36', 'versionType': 'semver'}, {'status': 'affected', 'version': '0', 'lessThan': '7.0.13', 'versionType': 'semver'}], 'programFiles': ['include/net/bluetooth/l2cap.h', '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': 'unaffected', 'version': '5.10.259', 'versionType': 'semver', 'lessThanOrEqual': '5.10.*'}, {'status': 'unaffected', 'version': '5.15.210', 'versionType': 'semver', 'lessThanOrEqual': '5.15.*'}, {'status': 'unaffected', 'version': '6.1.176', 'versionType': 'semver', 'lessThanOrEqual': '6.1.*'}, {'status': 'unaffected', 'version': '6.6.143', 'versionType': 'semver', 'lessThanOrEqual': '6.6.*'}, {'status': 'unaffected', 'version': '6.12.94', 'versionType': 'semver', 'lessThanOrEqual': '6.12.*'}, {'status': 'unaffected', 'version': '6.18.36', 'versionType': 'semver', 'lessThanOrEqual': '6.18.*'}, {'status': 'unaffected', 'version': '7.0.13', 'versionType': 'semver', 'lessThanOrEqual': '7.0.*'}, {'status': 'unaffected', 'version': '7.1', 'versionType': 'original_commit_for_fix', 'lessThanOrEqual': '*'}], 'programFiles': ['include/net/bluetooth/l2cap.h', 'net/bluetooth/l2cap_core.c'], 'defaultStatus': 'affected'}]
    Added Description In the Linux kernel, the following vulnerability has been resolved: Bluetooth: L2CAP: reject BR/EDR signaling packets over MTUsig net/bluetooth/l2cap_core.c:l2cap_sig_channel() accepts BR/EDR signaling packets up to the channel MTU and dispatches each command without enforcing the signaling MTU (MTUsig). A Bluetooth BR/EDR peer within radio range can send a fixed-channel CID 0x0001 packet that is larger than MTUsig and contains many L2CAP_ECHO_REQ commands before pairing. In a real-radio stock-kernel run, one 681-byte signaling packet containing 168 zero-length ECHO_REQ commands made the target transmit 168 ECHO_RSP frames over about 220 ms. Impact: a Bluetooth BR/EDR peer within radio range, before pairing, can force 168 ECHO_RSP frames from one 681-byte fixed-channel signaling packet containing packed ECHO_REQ commands. Define Linux's BR/EDR signaling MTU as the spec minimum of 48 bytes and reject any larger signaling packet with one L2CAP_COMMAND_REJECT_RSP carrying L2CAP_REJ_MTU_EXCEEDED before any command is dispatched. The Bluetooth Core spec wording for MTUExceeded says the reject identifier shall match the first request command in the packet, and that packets containing only responses shall be silently discarded. Linux intentionally deviates from that prescription: silently discarding desynchronizes the peer because the remote stack never learns its responses were dropped, and locating the first request command requires walking command headers past MTUsig, i.e. processing bytes from a packet we have already decided is too large to process. We therefore always emit one reject and use the identifier from the first command header, a single fixed-offset byte read. The unrestricted BR/EDR signaling parser and ECHO_REQ response path both trace to the initial git import; no later introducing commit is available for a Fixes tag.
    Added Reference https://git.kernel.org/stable/c/214a2042b16b3c8d798a8b9ef9f36094f13a9859
    Added Reference https://git.kernel.org/stable/c/a8335f3db15bd1e0e82e0db5d488fabc7d10d1ab
    Added Reference https://git.kernel.org/stable/c/b20e8a98dd29b121f58fcdf51e8576119aba536a
    Added Reference https://git.kernel.org/stable/c/dd214733544427587a95f66dbf3adff072568990
    Added Reference https://git.kernel.org/stable/c/dedc92b96dc1d8919a3bdf2495ede68922ef7ebc
    Added Reference https://git.kernel.org/stable/c/e05c4ac575b457978a7ef441053394169084869c
    Added Reference https://git.kernel.org/stable/c/e2b8acf9405bd9b1baf1c54dc897b0905db689bf
    Added Reference https://git.kernel.org/stable/c/fa5823126239b3e453fac1a2fe50726c7f4a55e1
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.