CVE-2022-48875 in Linux
Summary
by MITRE • 08/21/2024
In the Linux kernel, the following vulnerability has been resolved:
wifi: mac80211: sdata can be NULL during AMPDU start
ieee80211_tx_ba_session_handle_start() may get NULL for sdata when a deauthentication is ongoing.
Here a trace triggering the race with the hostapd test multi_ap_fronthaul_on_ap:
(gdb) list *drv_ampdu_action+0x46 0x8b16 is in drv_ampdu_action (net/mac80211/driver-ops.c:396). 391 int ret = -EOPNOTSUPP; 392 393 might_sleep(); 394 395 sdata = get_bss_sdata(sdata); 396 if (!check_sdata_in_driver(sdata)) 397 return -EIO; 398 399 trace_drv_ampdu_action(local, sdata, params); 400
wlan0: moving STA 02:00:00:00:03:00 to state 3 wlan0: associated wlan0: deauthenticating from 02:00:00:00:03:00 by local choice (Reason: 3=DEAUTH_LEAVING) wlan3.sta1: Open BA session requested for 02:00:00:00:00:00 tid 0 wlan3.sta1: dropped frame to 02:00:00:00:00:00 (unauthorized port) wlan0: moving STA 02:00:00:00:03:00 to state 2 wlan0: moving STA 02:00:00:00:03:00 to state 1 wlan0: Removed STA 02:00:00:00:03:00 wlan0: Destroyed STA 02:00:00:00:03:00 BUG: unable to handle page fault for address: fffffffffffffb48 PGD 11814067 P4D 11814067 PUD 11816067 PMD 0 Oops: 0000 [#1] PREEMPT SMP PTI
CPU: 2 PID: 133397 Comm: kworker/u16:1 Tainted: G W 6.1.0-rc8-wt+ #59 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.0-20220807_005459-localhost 04/01/2014 Workqueue: phy3 ieee80211_ba_session_work [mac80211]
RIP: 0010:drv_ampdu_action+0x46/0x280 [mac80211]
Code: 53 48 89 f3 be 89 01 00 00 e8 d6 43 bf ef e8 21 46 81 f0 83 bb a0 1b 00 00 04 75 0e 48 8b 9b 28 0d 00 00 48 81 eb 10 0e 00 00 93 58 09 00 00 f6 c2 20 0f 84 3b 01 00 00 8b 05 dd 1c 0f 00 85 RSP: 0018:ffffc900025ebd20 EFLAGS: 00010287 RAX: 0000000000000000 RBX: fffffffffffff1f0 RCX: ffff888102228240 RDX: 0000000080000000 RSI: ffffffff918c5de0 RDI: ffff888102228b40 RBP: ffffc900025ebd40 R08: 0000000000000001 R09: 0000000000000001 R10: 0000000000000001 R11: 0000000000000000 R12: ffff888118c18ec0 R13: 0000000000000000 R14: ffffc900025ebd60 R15: ffff888018b7efb8 FS: 0000000000000000(0000) GS:ffff88817a600000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: fffffffffffffb48 CR3: 0000000105228006 CR4: 0000000000170ee0 Call Trace: ieee80211_tx_ba_session_handle_start+0xd0/0x190 [mac80211]
ieee80211_ba_session_work+0xff/0x2e0 [mac80211]
process_one_work+0x29f/0x620 worker_thread+0x4d/0x3d0 ? process_one_work+0x620/0x620 kthread+0xfb/0x120 ? kthread_complete_and_exit+0x20/0x20 ret_from_fork+0x22/0x30
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Analysis
by VulDB Data Team • 03/07/2026
The vulnerability CVE-2022-48875 resides within the Linux kernel's mac80211 subsystem, specifically affecting wireless networking functionality. This issue manifests as a race condition during the handling of AMPDU (Aggregate MAC Protocol Data Unit) operations, where the sdata structure can become NULL during the start of an AMPDU session. The root cause stems from a timing window between deauthentication processes and AMPDU session initiation, creating a scenario where the system attempts to access a null pointer, leading to kernel page faults and potential system crashes. The vulnerability is particularly concerning as it occurs during normal wireless operation when a station is being deauthenticated while an AMPDU session is being established, presenting a direct path to kernel memory corruption.
The technical flaw occurs within the ieee80211_tx_ba_session_handle_start function which calls drv_ampdu_action without proper validation of the sdata pointer. When a deauthentication process is underway, the sdata structure may be in the process of being destroyed or has already been freed, yet the AMPDU start operation continues to reference it. The kernel trace shows that during this race condition, the system attempts to dereference a NULL pointer at address ffffffffff000000, resulting in a page fault exception. This vulnerability is classified under CWE-476 as a NULL pointer dereference, which represents a classic memory safety issue where code fails to check for null values before accessing pointers. The race condition specifically exploits the temporal gap between when a station is marked for removal and when all references to it are properly cleaned up, allowing for concurrent access to freed memory structures.
The operational impact of this vulnerability extends beyond simple system crashes to potentially enabling privilege escalation or denial of service attacks in wireless networking environments. When exploited, the vulnerability can cause the kernel to panic and reboot the entire system, disrupting wireless connectivity for all users on the affected network. This presents a significant risk in enterprise and infrastructure environments where wireless access points serve multiple clients, as a single malicious or misconfigured client could trigger system-wide outages. The vulnerability affects wireless drivers that implement the mac80211 framework, making it particularly relevant to devices running Linux kernel versions that incorporate the affected code paths. From an attacker perspective, this vulnerability aligns with ATT&CK technique T1068 by providing a path for privilege escalation through kernel memory corruption, while also supporting T1499 for system disruption.
Mitigation strategies for CVE-2022-48875 focus primarily on applying the kernel patch that resolves the race condition by ensuring proper synchronization between deauthentication and AMPDU session management. The fix involves adding additional checks to verify that sdata structures remain valid before proceeding with AMPDU operations, preventing the NULL pointer dereference. System administrators should prioritize updating to kernel versions that include this fix, particularly those containing the commit that addresses the specific race condition in the mac80211 subsystem. Additionally, monitoring for unusual deauthentication patterns and AMPDU session initiation sequences can help detect potential exploitation attempts. Organizations should also consider implementing network segmentation and access controls to limit the impact of potential exploitation, while maintaining regular kernel update schedules to ensure protection against similar vulnerabilities. The fix demonstrates proper defensive programming practices by incorporating proper null pointer validation and synchronization mechanisms that align with security best practices for kernel development.