Linux Kernel Bluetooth L2CAP Info RSP OOB Read CVE-2026-31393
CVE-2026-31393 Published on April 3, 2026
Bluetooth: L2CAP: Validate L2CAP_INFO_RSP payload length before access
In the Linux kernel, the following vulnerability has been resolved:
Bluetooth: L2CAP: Validate L2CAP_INFO_RSP payload length before access
l2cap_information_rsp() checks that cmd_len covers the fixed
l2cap_info_rsp header (type + result, 4 bytes) but then reads
rsp->data without verifying that the payload is present:
- L2CAP_IT_FEAT_MASK calls get_unaligned_le32(rsp->data), which reads
4 bytes past the header (needs cmd_len >= 8).
- L2CAP_IT_FIXED_CHAN reads rsp->data[0], 1 byte past the header
(needs cmd_len >= 5).
A truncated L2CAP_INFO_RSP with result == L2CAP_IR_SUCCESS triggers an
out-of-bounds read of adjacent skb data.
Guard each data access with the required payload length check. If the
payload is too short, skip the read and let the state machine complete
with safe defaults (feat_mask and remote_fixed_chan remain zero from
kzalloc), so the info timer cleanup and l2cap_conn_start() still run
and the connection is not stalled.
Products Associated with CVE-2026-31393
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Affected Versions
Linux:- Version 4e8402a3f884427f9233ba436459c158d1f2e114 and below 3b646516cba2ebc4b51a72954903326e7c1e443f is affected.
- Version 4e8402a3f884427f9233ba436459c158d1f2e114 and below 807bd1258453c4c83f6ae9dbc1e7b44860ff40d0 is affected.
- Version 4e8402a3f884427f9233ba436459c158d1f2e114 and below 9aeacde4da0f02d42fd968fd32f245828b230171 is affected.
- Version 4e8402a3f884427f9233ba436459c158d1f2e114 and below e7ff754e339e3d5ce29aa9f95352d0186df8fbd9 is affected.
- Version 4e8402a3f884427f9233ba436459c158d1f2e114 and below db2872d054e467810078e2b9f440a5b326a601b2 is affected.
- Version 4e8402a3f884427f9233ba436459c158d1f2e114 and below dd815e6e3918dc75a49aaabac36e4f024d675101 is affected.
- Version 2.6.24 is affected.
- Before 2.6.24 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.