# CVE-2026-74411: wifi: rtw89: Correct data type for scan index to avoid infinite loop

> An integer overflow in the rtw89 Wi-Fi driver causes an infinite loop during 6GHz scanning, leading to a system panic and denial of service.

- **Severity:** High 8.8 (`CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 15 Aug 2026
- **Updated:** 16 Oct 2026
- **Also known as:** BELL-CVE-2026-74411, DEBIAN-CVE-2026-74411, GHSA-75cw-hg5p-hxfv, UBUNTU-CVE-2026-74411

## What is CVE-2026-74411?

CVE-2026-74411 is a high-severity vulnerability in Linux, published on 15 Aug 2026. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

In the Linux kernel, the following vulnerability has been resolved:

wifi: rtw89: Correct data type for scan index to avoid infinite loop

A kernel soft lockup was observed during Wi-Fi scanning on the 6GHz band.
The CPU becomes stuck in rtw89_hw_scan_add_chan_ax for over 20 seconds,
leading to a system panic.

RIP points to 0f b6 c3 (movzbl %bl, %eax), which zero-extends
the low 8 bits of RBX into RAX.
RBX (the counter i) has reached a huge value: 0x137466a1.

  watchdog: BUG: soft lockup - CPU#2 stuck for 26s! [kworker/u16:4:6124]
  Workqueue: events_unbound cfg80211_wiphy_work [cfg80211]
  RIP: 0010:rtw89_hw_scan_add_chan_ax+0xb3/0x6e0 [rtw89_core]
  Code: a0 48 89 45 a8 44 89 6d 9c 44 89 75 98 eb 29 66 66 2e 0f 1f
  84 00 00 00 00 00 66 66 2e 0f 1f 84 00 00 00 00 00 66 90 83 c3 01
  <0f> b6 c3 41 3b 44 24 74 0f 83 0b 02 00 00 0f b6 c3 48 8d 14 80 49
  RSP: 0018:ffffcb48cbaa39f8 EFLAGS: 00000202
  RAX: 0000000000000005 RBX: 00000000137466a1 RCX: 0000000000000000
  RDX: ffff89ffc9d851a8 RSI: 0000000000004f0d RDI: 0000000096af0130
  RBP: ffffcb48cbaa3a60 R08: 0000000000000000 R09: ffff8a00b7502080
  R10: ffff8a00b75ff600 R11: 0000000000000000 R12: ffff89ffc7553870
  R13: ffff8a00b7ac8f19 R14: ffff8a00b75020d8 R15: ffff89ffc3d54d80
  FS:  0000000000000000(0000) GS:ffff8a014f962000(0000)
  knlGS:0000000000000000
  CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
  CR2: 00007558d7f9f4c4 CR3: 0000000178040001 CR4: 00000000001706f0
  Call Trace:
   <TASK>
   rtw89_hw_scan_prep_chan_list_ax+0x8a/0x400 [rtw89_core]
   rtw89_hw_scan_start+0x546/0x8a0 [rtw89_core]
   ? rtw89_fw_h2c_default_cmac_tbl+0x13c/0x1f0 [rtw89_core]
   rtw89_ops_hw_scan+0xae/0x120 [rtw89_core]
   drv_hw_scan+0xbb/0x180 [mac80211]
   __ieee80211_start_scan+0x2fc/0x750 [mac80211]
   ieee80211_request_scan+0xe/0x20 [mac80211]
   ieee80211_scan+0x123/0x190 [mac80211]
   rdev_scan+0x40/0x110 [cfg80211]
   cfg80211_scan_6ghz+0x5a1/0xa30 [cfg80211]

By objdump with source:

	for (i = 0; i < req->n_6ghz_params; i++) {
   5fbc0:	83 c3 01             	add    $0x1,%ebx --> i++
   5fbc3:	0f b6 c3             	movzbl %bl,%eax  --> get counter
   fbc6:	41 3b 44 24 74       	cmp    0x74(%r12),%eax

   * RBX: 00000000137466a1 -> %bl = a1 -> EAX = 000000a1 (161)

## Which versions are affected by CVE-2026-74411?


## How do I fix CVE-2026-74411?

Apply the vendor's patch.

## Is CVE-2026-74411 being exploited?

There is no known exploitation of CVE-2026-74411 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-74411 and fix it if it is affected.

What it is: CVE-2026-74411 is a high-severity vulnerability in Linux, published on 15 Aug 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-74411 in the wild and no public exploit code.

Affected product: Linux. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-74411/ (Markdown: https://insights.sbomify.com/CVE-2026-74411/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-74411
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-74411
- OSV: https://osv.dev/vulnerability/CVE-2026-74411

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-74411/
Summaries are generated and may contain mistakes; the official description above is the record.