CVE-2026-31513
CVE-2026-31513
In the Linux kernel, the following vulnerability has been resolved: Bluetooth: L2CAP: Fix stack-out-of-bounds read in l2cap_ecred_conn_req Syzbot reported a KASAN stack-out-of-bounds read in l2cap_build_cmd() that is triggered by a malformed Enhanced Credit Based Connection Request. The vulnerability stems from l2cap_ecred_conn_req(). The function allocates a local stack buffer (`pdu`) designed to hold a maximum of 5 Source Channel IDs (SCIDs), totaling 18 bytes. When an attacker sends a request with more than 5 SCIDs, the function calculates `rsp_len` based on this unvalidated `cmd_len` before checking if the number of SCIDs exceeds L2CAP_ECRED_MAX_CID. If the SCID count is too high, the function correctly jumps to the `response` label to reject the packet, but `rsp_len` retains the attacker's oversized value. Consequently, l2cap_send_cmd() is instructed to read past the end of the 18-byte `pdu` buffer, triggering a KASAN panic. Fix this by moving the assignment of `rsp_len` to after the `num_scid` boundary check. If the packet is rejected, `rsp_len` will safely remain 0, and the error response will only read the 8-byte base header from the stack.
Fixes and workarounds
Fix
The reporting source identifies this reference as a patch. Check the advisory for affected versions and supported release branches.
Source: 416baaa9-dc9f-4396-8d5f-8c081fb06d67Fix
The reporting source identifies this reference as a patch. Check the advisory for affected versions and supported release branches.
Source: 416baaa9-dc9f-4396-8d5f-8c081fb06d67Fix
The reporting source identifies this reference as a patch. Check the advisory for affected versions and supported release branches.
Source: 416baaa9-dc9f-4396-8d5f-8c081fb06d67Fix
The reporting source identifies this reference as a patch. Check the advisory for affected versions and supported release branches.
Source: 416baaa9-dc9f-4396-8d5f-8c081fb06d67Affected products and versions
| Product | Versions | Authority |
|---|---|---|
| linux_kernel linux |
≥ 6.12.75; < 6.12.80 (affected, custom) | NVD |
| linux_kernel linux |
≥ 6.18.16; < 6.18.21 (affected, custom) | NVD |
| linux_kernel linux |
≥ 6.19.6; < 6.19.11 (affected, custom) | NVD |
Version ranges are source assertions. Check the vendor advisory and your installed configuration before determining exposure.
NVD applicability configurations (1)
These expressions retain AND/OR operators, negation, and required environmental products. A listed product is not sufficient to establish exposure when additional conditions apply.
[
{
"negate": false,
"nodes": [
{
"cpeMatch": [
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "6.12.80",
"versionStartIncluding": "6.12.75",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "6.18.21",
"versionStartIncluding": "6.18.16",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "6.19.11",
"versionStartIncluding": "6.19.6",
"vulnerable": true
}
],
"negate": false,
"operator": "OR"
}
],
"operator": "OR"
}
]CVSS assessments
| Version / score | Vector | Authority |
|---|---|---|
| 3.1 / 8.1 high |
CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H | NVD: 416baaa9-dc9f-4396-8d5f-8c081fb06d67 |
Exploit evidence
No exploit evidence in collected sources. This is not proof of no exploitation.
References
- https://git.kernel.org/stable/c/5b35f8211a913cfe7ab9d54fa36a272d2059a588416baaa9-dc9f-4396-8d5f-8c081fb06d67 · Patch
- https://git.kernel.org/stable/c/9d87cb22195b2c67405f5485d525190747ad5493416baaa9-dc9f-4396-8d5f-8c081fb06d67 · Patch
- https://git.kernel.org/stable/c/a3d9c50d69785ae02e153f000da1b5fd6dbfdf1b416baaa9-dc9f-4396-8d5f-8c081fb06d67 · Patch
- https://git.kernel.org/stable/c/c8e1a27edb8b4e5afb56b384acd7b6c2dec1b7cc416baaa9-dc9f-4396-8d5f-8c081fb06d67 · Patch
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