CVE-2026-53208: Linux kernel · Bluetooth: L2CAP: reject BR/EDR signaling packets over MTUsig
Affects Linux kernelSource GCVE Database
Not known to be exploited · CVSS 5.5 Medium · fixed in 5.15.0-1117.124~20.04.1 : update Linux kernel when convenient.
Data as of 26 Oct 2026, 14:05 UTC
- EPSS
- 0.1% chance of exploitation in 30 days – higher than 2% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
- Patch
- Available – fixed in 5.15.0-1117.124~20.04.1, 5.15.0-1123.132~20.04.1, 5.15.0-1122.131~20.04.1 +68
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:HExploitation evidence
Disclosed: evidence found.
CVE published 25 Jun 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.
What to do
Upgrade to a fixed release listed under Affected software.
Affected software
| Product | Affected | Fixed in |
|---|---|---|
Ubuntu 26.04 LTSlinuxpkg:deb/ubuntu/linux?arch=source&distro=resoluteOther threats | Affected
| Fixed in
|
Ubuntu 26.04 LTSlinux-awspkg:deb/ubuntu/linux-aws?arch=source&distro=resoluteOther threats | Affected
| Fixed in
|
Ubuntu 26.04 LTSlinux-azurepkg:deb/ubuntu/linux-azure?arch=source&distro=resoluteOther threats | Affected
| Fixed in
|
Ubuntu 26.04 LTSlinux-azure-fdepkg:deb/ubuntu/linux-azure-fde?arch=source&distro=resoluteOther threats | Affected
| Fixed in– |
Ubuntu 26.04 LTSlinux-gcppkg:deb/ubuntu/linux-gcp?arch=source&distro=resoluteOther threats | Affected
| Fixed in
|
Ubuntu 26.04 LTSlinux-gkepkg:deb/ubuntu/linux-gke?arch=source&distro=resoluteOther threats | Affected
| Fixed in
|
Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.
AI-suggested
A fix is available and included in Linux kernel versions 5.15.0-1117.124~20.04.1 and later. Users and administrators should update to these or newer kernel versions to mitigate this vulnerability. No additional action is required beyond applying the official kernel update.
Description
A vulnerability in the Linux kernel Bluetooth L2CAP implementation allowed BR/EDR signaling packets larger than the signaling MTU to be accepted and processed. This could enable a Bluetooth BR/EDR peer within radio range, before pairing, to send a specially crafted packet containing many L2CAP_ECHO_REQ commands, causing the target to transmit numerous ECHO_RSP frames. The issue was resolved by enforcing the signaling MTU limit and rejecting oversized signaling packets with a proper L2CAP_COMMAND_REJECT_RSP response. The fix is included in Linux kernel versions 5.15.0-1117.124~20.04.1 and later.
References
- ubuntu.com/security/CVE-2026-53208 (opens in a new tab)
- cve.org/CVERecord?id=CVE-2026-53208 (opens in a new tab)
- git.kernel.org/linus/dd214733544427587a95f66dbf3adff072568990 (opens in a new tab)
- git.kernel.org/stable/c/214a2042b16b3c8d798a8b9ef9f36094f13a9859 (opens in a new tab)
- git.kernel.org/stable/c/a8335f3db15bd1e0e82e0db5d488fabc7d10d1ab (opens in a new tab)
- git.kernel.org/stable/c/b20e8a98dd29b121f58fcdf51e8576119aba536a (opens in a new tab)
- git.kernel.org/stable/c/dd214733544427587a95f66dbf3adff072568990 (opens in a new tab)
- git.kernel.org/stable/c/dedc92b96dc1d8919a3bdf2495ede68922ef7ebc (opens in a new tab)
- git.kernel.org/stable/c/e05c4ac575b457978a7ef441053394169084869c (opens in a new tab)
- git.kernel.org/stable/c/e2b8acf9405bd9b1baf1c54dc897b0905db689bf (opens in a new tab)
- git.kernel.org/stable/c/fa5823126239b3e453fac1a2fe50726c7f4a55e1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8726-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8727-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8728-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8760-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8726-2 (opens in a new tab)
- ubuntu.com/security/notices/USN-8726-3 (opens in a new tab)
- ubuntu.com/security/notices/USN-8800-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8760-2 (opens in a new tab)
- ubuntu.com/security/notices/USN-8728-2 (opens in a new tab)