CVE-2026-53208

Bluetooth reply amplification via unenforced signaling MTU

Published Jun 25, 2026 · Updated Jun 25, 2026

Improper L2CAP signaling validation in Linux Kernel allows physically proximate attackers to amplify Bluetooth replies before pairing. The l2cap_sig_channel() path accepts BR/EDR fixed-channel packets above the 48-byte signaling MTU and dispatches every packed ECHO_REQ. A peer within radio range needs no pairing and can turn one 681-byte packet into 168 ECHO_RSP frames, consuming Bluetooth airtime and processing without reported crash or data impact.

CVSS severity5.5
Medium
EPSS probability0.12%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Improper L2CAP signaling validation in Linux Kernel allows physically proximate attackers to amplify Bluetooth replies before pairing. The l2cap_sig_channel() path accepts BR/EDR fixed-channel packets above the 48-byte signaling MTU and dispatches every packed ECHO_REQ. A peer within radio range needs no pairing and can turn one 681-byte packet into 168 ECHO_RSP frames, consuming Bluetooth airtime and processing without reported crash or data impact.

The record

CVE
CVE-2026-53208
Published
Jun 25, 2026
Updated
Jun 25, 2026
Vendor
The Linux Kernel Organization
Product
Linux Kernel
Classifications
T1499.004
Attack vector
adjacent
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jun 25, 2026CVE publishedPublication date reported by the CVE source.
  2. Jun 25, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=0 <5.10.259
  2. Affected versionversion=0 <5.15.210
  3. Affected versionversion=0 <6.1.176
  4. Affected versionversion=0 <6.12.94
  5. Affected versionversion=0 <6.18.36
  6. Affected versionversion=0 <6.6.143
  7. Affected versionversion=0 <7.0.13
  8. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <214a2042b16b3c8d798a8b9ef9f36094f13a9859
  9. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <a8335f3db15bd1e0e82e0db5d488fabc7d10d1ab
  10. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <b20e8a98dd29b121f58fcdf51e8576119aba536a
  11. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <dd214733544427587a95f66dbf3adff072568990
  12. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <dedc92b96dc1d8919a3bdf2495ede68922ef7ebc
  13. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <e05c4ac575b457978a7ef441053394169084869c
  14. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <e2b8acf9405bd9b1baf1c54dc897b0905db689bf
  15. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <fa5823126239b3e453fac1a2fe50726c7f4a55e1

What conditions does exploitation require?

Attack vectoradjacent
Required privilegesunauthenticated

What is affected?

The Linux Kernel Organization · Linux Kernelversion=0 <5.10.259; version=0 <5.15.210; version=0 <6.1.176; version=0 <6.12.94; version=0 <6.18.36; version=0 <6.6.143; version=0 <7.0.13; version=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <214a2042b16b3c8d798a8b9ef9f36094f13a9859; version=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <a8335f3db15bd1e0e82e0db5d488fabc7d10d1ab; version=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <b20e8a98dd29b121f58fcdf51e8576119aba536a; version=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <dd214733544427587a95f66dbf3adff072568990; version=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <dedc92b96dc1d8919a3bdf2495ede68922ef7ebc; version=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <e05c4ac575b457978a7ef441053394169084869c; version=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <e2b8acf9405bd9b1baf1c54dc897b0905db689bf; version=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <fa5823126239b3e453fac1a2fe50726c7f4a55e1

Published CVSS scores

5.5NIST NVDCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectoradjacent
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

T1499.004Application or System Exploitation

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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