CVE-2025-40321 — wifi: brcmfmac: fix crash while sending Action Frames in standalone AP Mode
In the Linux kernel, the following vulnerability has been resolved: wifi: brcmfmac: fix crash while sending Action Frames in standalone AP Mode Currently, whenever there is a need to transmit an Action frame, the brcmfmac driver always uses the P2P vif to send the "actframe" IOVAR to firmware. The P2P interfaces were available when wpa_supplicant is managing the wlan interface. However, the P2P interfaces are not created/initialized when only hostapd is managing the wlan interface. And if hostapd receives an ANQP Query REQ Action frame even from an un-associated STA, the brcmfmac driver tries to use an uninitialized P2P vif pointer for sending the IOVAR to firmware. This NULL pointer dereferencing triggers a driver crash. [ 1417.074538] Unable to handle kernel NULL pointer dereference at virtual address 0000000000000000 [...] [ 1417.075188] Hardware name: Raspberry Pi 4 Model B Rev 1.5 (DT) [...] [ 1417.075653] Call trace: [ 1417.075662] brcmf_p2p_send_action_frame+0x23c/0xc58 [brcmfmac] [ 1417.075738] brcmf_cfg80211_mgmt_tx+0x304/0x5c0 [brcmfmac] [ 1417.075810] cfg80211_mlme_mgmt_tx+0x1b0/0x428 [cfg80211] [ 1417.076067] nl80211_tx_mgmt+0x238/0x388 [cfg80211] [ 1417.076281] genl_family_rcv_msg_doit+0xe0/0x158 [ 1417.076302] genl_rcv_msg+0x220/0x2a0 [ 1417.076317] netlink_rcv_skb+0x68/0x140 [ 1417.076330] genl_rcv+0x40/0x60 [ 1417.076343] netlink_unicast+0x330/0x3b8 [ 1417.076357] netlink_sendmsg+0x19c/0x3f8 [ 1417.076370] __sock_sendmsg+0x64/0xc0 [ 1417.076391] ____sys_sendmsg+0x268/0x2a0 [ 1417.076408] ___sys_sendmsg+0xb8/0x118 [ 1417.076427] __sys_sendmsg+0x90/0xf8 [ 1417.076445] __arm64_sys_sendmsg+0x2c/0x40 [ 1417.076465] invoke_syscall+0x50/0x120 [ 1417.076486] el0_svc_common.constprop.0+0x48/0xf0 [ 1417.076506] do_el0_svc+0x24/0x38 [ 1417.076525] el0_svc+0x30/0x100 [ 1417.076548] el0t_64_sync_handler+0x100/0x130 [ 1417.076569] el0t_64_sync+0x190/0x198 [ 1417.076589] Code: f9401e80 aa1603e2 f9403be1 5280e483 (f9400000) Fix this, by always using the vif corresponding to the wdev on which the Action frame Transmission request was initiated by the userspace. This way, even if P2P vif is not available, the IOVAR is sent to firmware on AP vif and the ANQP Query RESP Action frame is transmitted without crashing the driver. Move init_completion() for "send_af_done" from brcmf_p2p_create_p2pdev() to brcmf_p2p_attach(). Because the former function would not get executed when only hostapd is managing wlan interface, and it is not safe to do reinit_completion() later in brcmf_p2p_tx_action_frame(), without any prior init_completion(). And in the brcmf_p2p_tx_action_frame() function, the condition check for P2P Presence response frame is not needed, since the wpa_supplicant is properly sending the P2P Presense Response frame on the P2P-GO vif instead of the P2P-Device vif. [Cc stable]
Who exploits it and how urgent it is
A 0–100 score combining confirmed exploitation, ransomware and APT use, public exploits, EPSS and severity.
How the score was calculated
- EPSS 0.2% (30-day exploitation probability)+1
The score orders the patch queue; it does not replace your asset context (internet exposure, criticality, compensating controls).
Triage
Is it exploited, how likely is exploitation, what does it touch, and how severe do the sources call it.
Remediation
Fixes and mitigations documented by the sources — linked to the original advisory.
No fix documented by the sources we poll. That does not mean none exists: check the vendor advisory.
First 24 hours
Ordered from the record’s own fields — exposure first, because you cannot patch what you have not found. A rule-generated starting point.
- Identify exposed assets running the affected vendor/product/version combinations (Linux Linux).
- No fix documented in the sources: reduce exposure and monitor the vendor advisory.
- Search available logs for exploit probes, errors and authentication anomalies.
Affected scope
Vendor, product and versions as the sources word them.
| Vendor | Product | Versions | Status | Source |
|---|---|---|---|---|
| Linux | Linux |
≥ 18e2f61db3b708e0a22ccc403cb6ab2203d6faab and < c863b9c7b4e9af0b7931cb791ec91971a50f1a25≥ 18e2f61db3b708e0a22ccc403cb6ab2203d6faab and < e1fc9afcce9139791260f962541282d47fbb508d≥ 18e2f61db3b708e0a22ccc403cb6ab2203d6faab and < 55f60a72a178909ece4e32987e4c642ba57e1cf4≥ 18e2f61db3b708e0a22ccc403cb6ab2203d6faab and < c2b0f8d3e7358c33d90f0e62765d474f25f26a45≥ 18e2f61db3b708e0a22ccc403cb6ab2203d6faab and < 64e3175d1c8a3bea02032e7c9d1befd5f43786fa≥ 18e2f61db3b708e0a22ccc403cb6ab2203d6faab and < a6eed58249e7d60f856900e682992300f770f64b≥ 18e2f61db3b708e0a22ccc403cb6ab2203d6faab and < dbc7357b6aae686d9404e1dd7e2e6cf92c3a1b5a≥ 18e2f61db3b708e0a22ccc403cb6ab2203d6faab and < 3776c685ebe5f43e9060af06872661de55e80b9a and 1 moreversion 3.9 |
Vulnerable | CVE Program (cve.org) e CISA ADP |
EPSS over time FIRST
Oct 13, 2026 → Oct 14, 2026 · 2 reading(s) · max 0.20%
Detection
Read off the CVSS vector and the weakness class. Starting points, not tested rules.
- Not enough vector or weakness data: use the affected application’s logs as a starting point.
Timeline
What happened to this CVE, newest first.
- 2026
- Record published
- Affected products added · linux/linux
- Source status changed · → Deferred
- Record created in this database
- 2025
- CVE published
Source activity
Repeated readings are counted rather than listed.
- 1× References added · Oct 14, 2026 – Oct 14, 2026
- 1× Official description updated · Oct 13, 2026 – Oct 13, 2026
References
10 on the record
- git.kernel.org/stable/c/64e3175d1c8a3bea02032e7c9d1befd5f43786fa
- git.kernel.org/stable/c/a6eed58249e7d60f856900e682992300f770f64b
- git.kernel.org/stable/c/c863b9c7b4e9af0b7931cb791ec91971a50f1a25
- git.kernel.org/stable/c/c2b0f8d3e7358c33d90f0e62765d474f25f26a45
- nvd.nist.gov/vuln/detail/CVE-2025-40321
- git.kernel.org/stable/c/3776c685ebe5f43e9060af06872661de55e80b9a
- git.kernel.org/stable/c/dbc7357b6aae686d9404e1dd7e2e6cf92c3a1b5a
- github.com/advisories/GHSA-px3f-ppm2-rx2r
- git.kernel.org/stable/c/55f60a72a178909ece4e32987e4c642ba57e1cf4
- git.kernel.org/stable/c/e1fc9afcce9139791260f962541282d47fbb508d
Elsewhere on this site
Related CVEs (same products)
- Critical CVE-2026-99999 ipv4: validate checksum_start before completing checksum 12h
- Unknown CVE-2026-98432 ipv4: free inet_opt and ireq_opt after an RCU grace period 12h
- Unknown CVE-2026-98431 RDMA/uverbs: Fix mmap_lock/disassociation_lock circular dependency 1d
- Unknown CVE-2026-98430 RDMA/efa: Keep admin queues alive while IRQ is registered 1d
- Unknown CVE-2026-98429 RDMA/efa: Keep EQ resources alive while IRQ is registered 1d
- Unknown CVE-2026-98428 ALSA: usb: 6fire: Avoid embedded URBs 1d
Not in any source we poll
Listed rather than left blank: an empty field and an unmeasured one look identical on screen, and only one is a reason to look elsewhere.
- No CVSS score published by NVD, the CNA, CISA or GitHub so far.
- No fixed version, patch or mitigation documented.
- No CISA SSVC assessment.
- No CWE classification.
- No confirmed IOCs, IP addresses, domains, file hashes, or malware artifacts supplied.
- No organization-specific asset inventory, compensating-control status, or patch deployment evidence supplied.
- No exploit packet captures, log samples, or incident case IDs supplied.
Answered from this record
Text assembled only from the fields above — no additional claims.
What should defenders know first?
CVE-2025-40321 is "wifi: brcmfmac: fix crash while sending Action Frames in standalone AP Mode", rated Unknown. It affects Linux (Linux); versions are in the scope table. It is not in CISA KEV, which does not rule out exploitation. EPSS 0.20% estimates the probability of exploitation in 30 days; neither replaces your asset context. First verify whether exposed or business-critical assets run the affected versions, apply vendor fixes or mitigations, and preserve logs for review.
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