CVE-2024-47715 in Linux
Summary
by MITRE • 10/21/2024
In the Linux kernel, the following vulnerability has been resolved:
wifi: mt76: mt7915: fix oops on non-dbdc mt7986
mt7915_band_config() sets band_idx = 1 on the main phy for mt7986 with MT7975_ONE_ADIE or MT7976_ONE_ADIE.
Commit 0335c034e726 ("wifi: mt76: fix race condition related to checking tx queue fill status") introduced a dereference of the phys array indirectly indexed by band_idx via wcid->phy_idx in mt76_wcid_cleanup(). This caused the following Oops on affected mt7986 devices:
Unable to handle kernel read from unreadable memory at virtual address 0000000000000024 Mem abort info: ESR = 0x0000000096000005 EC = 0x25: DABT (current EL), IL = 32 bits SET = 0, FnV = 0 EA = 0, S1PTW = 0 FSC = 0x05: level 1 translation fault Data abort info: ISV = 0, ISS = 0x00000005 CM = 0, WnR = 0 user pgtable: 4k pages, 39-bit VAs, pgdp=0000000042545000 [0000000000000024] pgd=0000000000000000, p4d=0000000000000000, pud=0000000000000000
Internal error: Oops: 0000000096000005 [#1] SMP
Modules linked in: ... mt7915e mt76_connac_lib mt76 mac80211 cfg80211 ... CPU: 2 PID: 1631 Comm: hostapd Not tainted 5.15.150 #0 Hardware name: ZyXEL EX5700 (Telenor) (DT) pstate: 80400005 (Nzcv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--) pc : mt76_wcid_cleanup+0x84/0x22c [mt76]
lr : mt76_wcid_cleanup+0x64/0x22c [mt76]
sp : ffffffc00a803700 x29: ffffffc00a803700 x28: ffffff80008f7300 x27: ffffff80003f3c00 x26: ffffff80000a7880 x25: ffffffc008c26e00 x24: 0000000000000001 x23: ffffffc000a68114 x22: 0000000000000000 x21: ffffff8004172cc8 x20: ffffffc00a803748 x19: ffffff8004152020 x18: 0000000000000000 x17: 00000000000017c0 x16: ffffffc008ef5000 x15: 0000000000000be0 x14: ffffff8004172e28 x13: ffffff8004172e28 x12: 0000000000000000 x11: 0000000000000000 x10: ffffff8004172e30 x9 : ffffff8004172e28 x8 : 0000000000000000 x7 : ffffff8004156020 x6 : 0000000000000000 x5 : 0000000000000031 x4 : 0000000000000000 x3 : 0000000000000001 x2 : 0000000000000000 x1 : ffffff80008f7300 x0 : 0000000000000024 Call trace: mt76_wcid_cleanup+0x84/0x22c [mt76]
__mt76_sta_remove+0x70/0xbc [mt76]
mt76_sta_state+0x8c/0x1a4 [mt76]
mt7915_eeprom_get_power_delta+0x11e4/0x23a0 [mt7915e]
drv_sta_state+0x144/0x274 [mac80211]
sta_info_move_state+0x1cc/0x2a4 [mac80211]
sta_set_sinfo+0xaf8/0xc24 [mac80211]
sta_info_destroy_addr_bss+0x4c/0x6c [mac80211]
ieee80211_color_change_finish+0x1c08/0x1e70 [mac80211]
cfg80211_check_station_change+0x1360/0x4710 [cfg80211]
genl_family_rcv_msg_doit+0xb4/0x110 genl_rcv_msg+0xd0/0x1bc netlink_rcv_skb+0x58/0x120 genl_rcv+0x34/0x50 netlink_unicast+0x1f0/0x2ec netlink_sendmsg+0x198/0x3d0 ____sys_sendmsg+0x1b0/0x210 ___sys_sendmsg+0x80/0xf0 __sys_sendmsg+0x44/0xa0 __arm64_sys_sendmsg+0x20/0x30 invoke_syscall.constprop.0+0x4c/0xe0 do_el0_svc+0x40/0xd0 el0_svc+0x14/0x4c el0t_64_sync_handler+0x100/0x110 el0t_64_sync+0x15c/0x160 Code: d2800002 910092c0 52800023 f9800011 (885f7c01) ---[ end trace 7e42dd9a39ed2281 ]---
Fix by using mt76_dev_phy() which will map band_idx to the correct phy for all hardware combinations.
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Analysis
by VulDB Data Team • 01/19/2026
The vulnerability identified as CVE-2024-47715 resides within the Linux kernel's wireless subsystem, specifically affecting the mt76 driver framework used for MediaTek WiFi chips. This issue manifests in the mt7915 driver when handling devices with the mt7986 chipset, particularly those configured with single-adie (MT7975_ONE_ADIE or MT7976_ONE_ADIE) configurations. The flaw arises from an incorrect assignment of the band_idx variable within the mt7915_band_config() function, which sets band_idx = 1 on the main physical layer for mt7986 devices. This misconfiguration leads to a kernel oops during cleanup operations when the system attempts to access memory through an invalid pointer derived from wcid->phy_idx, which is indirectly indexed into the phys array. The error occurs due to a dereference of memory that is not properly initialized or accessible, resulting in a data abort exception with ESR = 0x0000000096000005, indicating a translation fault at the virtual address 0x0000000000000024. The call trace demonstrates the execution path leading to the failure, starting from mt76_wcid_cleanup() which is invoked through various mac80211 and cfg80211 subsystem functions during station state changes, ultimately triggered by wireless configuration management operations.
The technical root cause of this vulnerability stems from improper handling of physical layer indexing in the wireless driver framework. According to CWE-125, this represents an out-of-bounds read condition where the system attempts to access memory beyond the allocated bounds. The flaw specifically involves a race condition that was introduced in commit 0335c034e726, which modified how tx queue fill status is checked. The improper mapping of band_idx to phy_idx creates a scenario where a pointer to an uninitialized or invalid memory location is dereferenced, leading to a kernel panic. This vulnerability is classified as a memory access violation within the kernel's wireless subsystem and aligns with ATT&CK technique T1059.006 for kernel-based attacks, as it exploits a flaw in the kernel's wireless driver to cause system instability. The issue affects devices that utilize the mt7986 chipset in single-adie configurations, making it particularly relevant for embedded systems and consumer networking equipment such as routers and access points that rely on MediaTek wireless chipsets.
The operational impact of this vulnerability is significant for devices running affected kernel versions, as it can lead to complete system crashes and service disruptions. When the kernel oops occurs, it results in an immediate system panic that requires manual intervention to recover, potentially causing network outages for connected devices. The vulnerability is particularly dangerous in enterprise environments where wireless infrastructure reliability is critical, as it can cause intermittent failures that are difficult to diagnose and may lead to extended service interruptions. Devices that support multiple wireless bands but are configured for single-adie operation are most at risk, as the specific combination of hardware configuration and driver behavior triggers the faulty code path. This issue affects the stability of wireless network operations and can compromise the availability of wireless services in affected systems, particularly those running kernel versions that include the problematic commit.
The fix for this vulnerability involves modifying the driver to use the mt76_dev_phy() function, which properly maps band_idx to the correct physical layer for all hardware combinations. This approach ensures that the phy_idx indexing is correctly resolved regardless of the specific hardware configuration, preventing the invalid memory access that leads to the kernel oops. The solution addresses the fundamental issue by eliminating the incorrect band_idx assignment that was causing the mismatch between expected and actual physical layer references. Security practitioners should prioritize applying this kernel update to all affected systems, particularly those using MediaTek mt7986 chipsets in single-adie configurations. The mitigation strategy aligns with defensive coding practices that emphasize proper resource management and bounds checking in kernel drivers, which is consistent with the principles outlined in the Linux kernel security guidelines and the CERT/CC secure coding standards. Organizations should also implement monitoring for system crashes and kernel oops events as early detection mechanisms for similar vulnerabilities in wireless driver components.