CVE-2026-53382 in Linux
Summary
by MITRE • 07/19/2026
In the Linux kernel, the following vulnerability has been resolved:
media: vidtv: fix NULL pointer dereference in vidtv_mux_push_si
syzbot reported a general protection fault in vidtv_psi_ts_psi_write_into [1].
vidtv_mux_get_pid_ctx() can return NULL, but vidtv_mux_push_si() does not check for this before dereferencing the returned pointer to access the continuity counter. This leads to a general protection fault when accessing a near-NULL address.
The root cause is that vidtv_mux_pid_ctx_init() does not check the return value of vidtv_mux_create_pid_ctx_once() for PMT section PIDs. If the allocation fails, the PID context is never created, but init returns success. The subsequent vidtv_mux_push_si() call then gets NULL from vidtv_mux_get_pid_ctx() and crashes.
Fix both the root cause (add error check in vidtv_mux_pid_ctx_init for PMT PIDs) and add defensive NULL checks in vidtv_mux_push_si for all vidtv_mux_get_pid_ctx() calls.
[1]
Oops: general protection fault, probably for non-canonical address 0xdffffc0000000000: 0000 [#1] SMP KASAN PTI
KASAN: null-ptr-deref in range [0x0000000000000000-0x0000000000000007]
Workqueue: events vidtv_mux_tick RIP: 0010:vidtv_psi_ts_psi_write_into+0x54a/0xbc0 drivers/media/test-drivers/vidtv/vidtv_psi.c:197 Call Trace: <TASK> vidtv_psi_table_header_write_into drivers/media/test-drivers/vidtv/vidtv_psi.c:799 [inline]
vidtv_psi_pmt_write_into+0x3b2/0xa70 drivers/media/test-drivers/vidtv/vidtv_psi.c:1231 vidtv_mux_push_si+0x932/0xe80 drivers/media/test-drivers/vidtv/vidtv_mux.c:196 vidtv_mux_tick+0xe9b/0x1480 drivers/media/test-drivers/vidtv/vidtv_mux.c:408
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Analysis
by VulDB Data Team • 07/19/2026
The vulnerability described represents a critical null pointer dereference in the Linux kernel's video test driver subsystem, specifically within the vidtv_mux_push_si function. This flaw exists within the media framework's test driver implementation and manifests as a general protection fault during kernel execution. The issue stems from improper error handling in the PID context initialization process, where vidtv_mux_pid_ctx_init fails to validate the return value of vidtv_mux_create_pid_ctx_once when processing PMT section PIDs. When memory allocation for PID contexts fails, the function incorrectly returns success while leaving the PID context uninitialized, creating a scenario where subsequent operations attempt to dereference a null pointer.
The technical execution path begins with vidtv_mux_get_pid_ctx() returning NULL due to failed initialization, followed by vidtv_mux_push_si() attempting to access the continuity counter field of this null pointer without proper validation. This direct dereference leads to a kernel panic through a general protection fault, as evidenced by the KASAN report indicating a null pointer dereference in the address range 0x0000000000000000-0x0000000000000007. The crash occurs during vidtv_psi_ts_psi_write_into execution, with stack trace showing the fault propagating through vidtv_psi_pmt_write_into and ultimately reaching vidtv_mux_push_si at line 196 in vidtv_mux.c.
This vulnerability aligns with CWE-476, which defines null pointer dereference as a common security weakness where software attempts to access memory through a pointer that has not been properly initialized. The flaw also maps to ATT&CK technique T1068, as it represents an improper input validation mechanism that could potentially allow for privilege escalation or system instability. The root cause analysis reveals that the fix must address both the immediate symptom and underlying cause, requiring defensive programming practices in vidtv_mux_push_si and mandatory error checking in vidtv_mux_pid_ctx_init. The operational impact includes potential kernel crashes, system instability, and denial of service conditions that could affect video processing applications relying on test driver functionality.
The mitigation strategy involves implementing comprehensive error validation throughout the PID context management process while maintaining robust defensive programming practices in the affected code paths. This dual approach ensures that allocation failures are properly detected and handled at both initialization and usage points, preventing null pointer dereferences from occurring in production environments. The fix pattern established here reflects industry best practices for kernel security hardening, emphasizing the importance of input validation and error handling in critical system components.