Linux Kernel Bluetooth L2CAP DoS via Multiple ECRED_CONN_REQ
CVE-2026-23395 Published on March 25, 2026
Bluetooth: L2CAP: Fix accepting multiple L2CAP_ECRED_CONN_REQ
In the Linux kernel, the following vulnerability has been resolved:
Bluetooth: L2CAP: Fix accepting multiple L2CAP_ECRED_CONN_REQ
Currently the code attempts to accept requests regardless of the
command identifier which may cause multiple requests to be marked
as pending (FLAG_DEFER_SETUP) which can cause more than
L2CAP_ECRED_MAX_CID(5) to be allocated in l2cap_ecred_rsp_defer
causing an overflow.
The spec is quite clear that the same identifier shall not be used on
subsequent requests:
'Within each signaling channel a different Identifier shall be used
for each successive request or indication.'
https://www.bluetooth.com/wp-content/uploads/Files/Specification/HTML/Core-62/out/en/host/logical-link-control-and-adaptation-protocol-specification.html#UUID-32a25a06-4aa4-c6c7-77c5-dcfe3682355d
So this attempts to check if there are any channels pending with the
same identifier and rejects if any are found.
Products Associated with CVE-2026-23395
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Affected Versions
Linux:- Version 15f02b91056253e8cdc592888f431da0731337b8 and below fb4a3a26483f3ea2cd21c7a2f7c45d5670600465 is affected.
- Version 15f02b91056253e8cdc592888f431da0731337b8 and below 2124d82fd25e1671bb3ceb37998af5aae5903e06 is affected.
- Version 15f02b91056253e8cdc592888f431da0731337b8 and below 6b949a6b33cbdf621d9fc6f0c48ac00915dbf514 is affected.
- Version 15f02b91056253e8cdc592888f431da0731337b8 and below 8d0d94f8ba5b3a0beec3b0da558b9bea48018117 is affected.
- Version 15f02b91056253e8cdc592888f431da0731337b8 and below e72ee455297b794b852e5cea8d2d7bb17312172a is affected.
- Version 15f02b91056253e8cdc592888f431da0731337b8 and below 5b3e2052334f2ff6d5200e952f4aa66994d09899 is affected.
- Version 5.7 is affected.
- Before 5.7 is unaffected.
- Version 6.1.167, <= 6.1.* is unaffected.
- Version 6.6.130, <= 6.6.* is unaffected.
- Version 6.12.78, <= 6.12.* is unaffected.
- Version 6.18.20, <= 6.18.* is unaffected.
- Version 6.19.10, <= 6.19.* is unaffected.
- Version 7.0-rc5, <= * is unaffected.