Bluetooth: L2CAP: Fix stack-out-of-bounds read in l2cap_ecred_conn_req
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.
CVE-2026-31513
Primary source · Revision 1
Imported from structured advisory data. Source references identify upstream records or fields; verify affected versions and your deployed configuration.
Security context
Source reference: cve:CVE-2026-31513
Linux
Source reference: /containers/cna/affected/0/product
- Affected versions
- Not stated in this record
- Fixed versions
- Not stated in this record
- Prerequisites
- Not stated in this record
Linux
Source reference: /containers/cna/affected/1/product
- Affected versions
- Not stated in this record
- Fixed versions
- Not stated in this record
- Prerequisites
- Not stated in this record
Structured affected-version data
Original package identities and version rules from this source.
[
{
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"product": "Linux",
"versions": [
{
"status": "affected",
"version": "935f324e4b2461df2cf7f02b4195082b4304c708",
"lessThan": "c8e1a27edb8b4e5afb56b384acd7b6c2dec1b7cc",
"versionType": "git"
},
{
"status": "affected",
"version": "e981a9392800ce2c5bca196a6ab2c55e9370efaa",
"lessThan": "5b35f8211a913cfe7ab9d54fa36a272d2059a588",
"versionType": "git"
},
{
"status": "affected",
"version": "f3fdf2e7276a3edc5df55454275da20eac186970",
"lessThan": "a3d9c50d69785ae02e153f000da1b5fd6dbfdf1b",
"versionType": "git"
},
{
"status": "affected",
"version": "c28d2bff70444a85b3b86aaf241ece9408c7858c",
"lessThan": "9d87cb22195b2c67405f5485d525190747ad5493",
"versionType": "git"
}
],
"programFiles": [
"net/bluetooth/l2cap_core.c"
],
"defaultStatus": "unaffected"
},
{
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"product": "Linux",
"versions": [
{
"status": "affected",
"version": "6.12.75",
"lessThan": "6.12.80",
"versionType": "semver"
},
{
"status": "affected",
"version": "6.18.16",
"lessThan": "6.18.21",
"versionType": "semver"
},
{
"status": "affected",
"version": "6.19.6",
"lessThan": "6.19.11",
"versionType": "semver"
}
],
"programFiles": [
"net/bluetooth/l2cap_core.c"
],
"defaultStatus": "unaffected"
}
]- Related CVEs
- CVE-2026-31513
Source reference:
/cveMetadata/cveId
Publisher severity
high
Source reference: /containers/cna/metrics
- Event
- #39913 · Revision 1
- Added to Heist Feed
- Publisher date