CVE-2026-93783

Bluetooth: RFCOMM: validate skb length in rfcomm_recv_frame

cve-program · severity unknownCVSS unknownCheck source for fixed versionsKEV status unknown

Original advisory

Historical advisory recorded 23 Oct 2026 15:48:27 UTC. Read the latest advisory.

cve-program · CVE-2026-93783

Published

In the Linux kernel, the following vulnerability has been resolved: Bluetooth: RFCOMM: validate skb length in rfcomm_recv_frame rfcomm_recv_frame() casts skb->data to struct rfcomm_hdr and dereferences hdr->addr and hdr->ctrl without validating skb->len first. A truncated frame with skb->len less than the minimum header size causes an out-of-bounds read of uninitialized memory. Additionally, a zero-length frame causes skb->len-- to underflow to UINT_MAX, making skb_tail_pointer() read far past the buffer. Commit 23882b828c3c ("Bluetooth: RFCOMM: validate skb length in MCC handlers") fixed the same class of missing-length-check bugs in the MCC sub-handlers, but the top-level rfcomm_recv_frame() was left unfixed. KMSAN reports: BUG: KMSAN: uninit-value in rfcomm_run ... Uninit was created at: __alloc_skb+0x474/0xb60 vhci_write+0xe9/0x870 Fix this by rejecting frames smaller than sizeof(struct rfcomm_hdr) + 1 (the minimum frame must have a 3-byte header and a 1-byte FCS).

Read the publisher's advisory

Affected versions, risk and source history

cve-program · CVE-2026-93783

Published

Linux

Vendor product

Publisher's version information

Shown as published. These rules are not interpreted as NuGet package version ranges.

{
                    "product": "Linux",
                    "vendor": "Linux",
                    "defaultStatus": "unaffected",
                    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
                    "programFiles": [
                        "net/bluetooth/rfcomm/core.c"
                    ],
                    "versions": [
                        {
                            "version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2",
                            "lessThan": "fb40eda15122f6b780228639c1ead6820340ff54",
                            "status": "affected",
                            "versionType": "git"
                        },
                        {
                            "version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2",
                            "lessThan": "3829af5fab5a22405bf1e7d69068c2ec0fce46ca",
                            "status": "affected",
                            "versionType": "git"
                        },
                        {
                            "version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2",
                            "lessThan": "b161eacd7fa4a2d765724b5504ac6cc388e48f80",
                            "status": "affected",
                            "versionType": "git"
                        },
                        {
                            "version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2",
                            "lessThan": "30d1d9f3495463f7c026e4c553127f79b486fcd6",
                            "status": "affected",
                            "versionType": "git"
                        },
                        {
                            "version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2",
                            "lessThan": "67dc3b40fae71b6b11c71e7ff69bac0758818c05",
                            "status": "affected",
                            "versionType": "git"
                        },
                        {
                            "version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2",
                            "lessThan": "bbc310caa2b6bf5fe42896ba27da0fbc12e4ac51",
                            "status": "affected",
                            "versionType": "git"
                        },
                        {
                            "version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2",
                            "lessThan": "b230e5bf501c5edaf2eb0991cb862ac142031d4b",
                            "status": "affected",
                            "versionType": "git"
                        }
                    ]
                }

Linux

Vendor product

Publisher's version information

Shown as published. These rules are not interpreted as NuGet package version ranges.

{
                    "product": "Linux",
                    "vendor": "Linux",
                    "defaultStatus": "affected",
                    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
                    "programFiles": [
                        "net/bluetooth/rfcomm/core.c"
                    ],
                    "versions": [
                        {
                            "version": "2.6.12",
                            "status": "affected"
                        },
                        {
                            "version": "0",
                            "lessThan": "2.6.12",
                            "status": "unaffected",
                            "versionType": "semver"
                        },
                        {
                            "version": "5.10.271",
                            "lessThanOrEqual": "5.10.*",
                            "status": "unaffected",
                            "versionType": "semver"
                        },
                        {
                            "version": "5.15.222",
                            "lessThanOrEqual": "5.15.*",
                            "status": "unaffected",
                            "versionType": "semver"
                        },
                        {
                            "version": "6.1.189",
                            "lessThanOrEqual": "6.1.*",
                            "status": "unaffected",
                            "versionType": "semver"
                        },
                        {
                            "version": "6.6.158",
                            "lessThanOrEqual": "6.6.*",
                            "status": "unaffected",
                            "versionType": "semver"
                        },
                        {
                            "version": "6.12.111",
                            "lessThanOrEqual": "6.12.*",
                            "status": "unaffected",
                            "versionType": "semver"
                        },
                        {
                            "version": "6.18.53",
                            "lessThanOrEqual": "6.18.*",
                            "status": "unaffected",
                            "versionType": "semver"
                        },
                        {
                            "version": "7.2",
                            "lessThanOrEqual": "*",
                            "status": "unaffected",
                            "versionType": "original_commit_for_fix"
                        }
                    ]
                }

Original source record · Cite this exact observation · Complete original publisher JSON