CVE-2026-23073

In the Linux kernel, the following vulnerability has been resolved:

wifi: rsi: Fix memory corruption due to not set vif driver data size

The struct ieee80211_vif contains trailing space for vif driver data, when struct ieee80211_vif is allocated, the total memory size that is allocated is sizeof(struct ieee80211_vif) + size of vif driver data. The size of vif driver data is set by each WiFi driver as needed.

The RSI911x driver does not set vif driver data size, no trailing space for vif driver data is therefore allocated past struct ieee80211_vif . The RSI911x driver does however use the vif driver data to store its vif driver data structure struct vif_priv. An access to vif->drv_priv leads to access out of struct ieee80211_vif bounds and corruption of some memory.

In case of the failure observed locally, rsi_mac80211_add_interface() would write struct vif_priv *vif_info = (struct vif_priv *)vif->drv_priv; vif_info->vap_id = vap_idx. This write corrupts struct fq_tin member struct list_head new_flows . The flow = list_first_entry(head, struct fq_flow, flowchain); in fq_tin_reset() then reports non-NULL bogus address, which when accessed causes a crash.

The trigger is very simple, boot the machine with init=/bin/sh , mount devtmpfs, sysfs, procfs, and then do ip link set wlan0 up, sleep 1, ip link set wlan0 down and the crash occurs.

Fix this by setting the correct size of vif driver data, which is the size of struct vif_priv, so that memory is allocated and the driver can store its driver data in it, instead of corrupting memory around it.

Weakness

The product writes data past the end, or before the beginning, of the intended buffer.

Affected Software

Potential Mitigations

• Use a language that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid.

• For example, many languages that perform their own memory management, such as Java and Perl, are not subject to buffer overflows. Other languages, such as Ada and C#, typically provide overflow protection, but the protection can be disabled by the programmer.

• Be wary that a language’s interface to native code may still be subject to overflows, even if the language itself is theoretically safe.

• Use a vetted library or framework that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid.

• Examples include the Safe C String Library (SafeStr) by Messier and Viega [REF-57], and the Strsafe.h library from Microsoft [REF-56]. These libraries provide safer versions of overflow-prone string-handling functions.

• Use automatic buffer overflow detection mechanisms that are offered by certain compilers or compiler extensions. Examples include: the Microsoft Visual Studio /GS flag, Fedora/Red Hat FORTIFY_SOURCE GCC flag, StackGuard, and ProPolice, which provide various mechanisms including canary-based detection and range/index checking.

• D3-SFCV (Stack Frame Canary Validation) from D3FEND [REF-1334] discusses canary-based detection in detail.

• Consider adhering to the following rules when allocating and managing an application’s memory:

• Run or compile the software using features or extensions that randomly arrange the positions of a program’s executable and libraries in memory. Because this makes the addresses unpredictable, it can prevent an attacker from reliably jumping to exploitable code.

• Examples include Address Space Layout Randomization (ASLR) [REF-58] [REF-60] and Position-Independent Executables (PIE) [REF-64]. Imported modules may be similarly realigned if their default memory addresses conflict with other modules, in a process known as “rebasing” (for Windows) and “prelinking” (for Linux) [REF-1332] using randomly generated addresses. ASLR for libraries cannot be used in conjunction with prelink since it would require relocating the libraries at run-time, defeating the whole purpose of prelinking.

• For more information on these techniques see D3-SAOR (Segment Address Offset Randomization) from D3FEND [REF-1335].

• Use a CPU and operating system that offers Data Execution Protection (using hardware NX or XD bits) or the equivalent techniques that simulate this feature in software, such as PaX [REF-60] [REF-61]. These techniques ensure that any instruction executed is exclusively at a memory address that is part of the code segment.

• For more information on these techniques see D3-PSEP (Process Segment Execution Prevention) from D3FEND [REF-1336].

References

• https://git.kernel.org/stable/c/0d7c9e793e351cbbe9e06a9ca47d77b6ad288fb0
• https://git.kernel.org/stable/c/31efbcff90884ea5f65bf3d1de01267db51ee3d1
• https://git.kernel.org/stable/c/49ef094fdbc3526e5db2aebb404b84f79c5603dc
• https://git.kernel.org/stable/c/4f431d88ea8093afc7ba55edf4652978c5a68f33
• https://git.kernel.org/stable/c/7761d7801f40e61069b4df3db88b36d80d089f8a
• https://git.kernel.org/stable/c/7c54d0c3e2cad4300be721ec2aecfcf8a63bc9f4
• https://git.kernel.org/stable/c/99129d80a5d4989ef8566f434f3589f60f28042b